阅读说明：本技术 一种钨镍合金靶材的制备方法 (Preparation method of tungsten-nickel alloy target material ) 是由 张灵杰 于 2021-05-31 设计创作，主要内容包括：本发明提供了一种钨镍合金靶材的制备方法,包括选取钨粉和镍粉或者与其它金属元素形成的多组元合金粉末粉末过筛处理的步骤、冷等静压步骤、烧结步骤、校直加工步骤、退火处理步骤、机加工步骤、洁净处理步骤,制得高钨镍合金靶材,本发明采用低温烧结和锻造工艺,实现高致密性、组织均匀、力学性能良好的钨镍合金靶材的制备,可广泛应用于玻璃镀膜、高速动能武器等领域。(The invention provides a preparation method of a tungsten-nickel alloy target material, which comprises the steps of selecting tungsten powder and nickel powder or multi-component alloy powder formed by the tungsten powder and the nickel powder and other metal elements, sieving, cold isostatic pressing, sintering, straightening, annealing, machining and cleaning to prepare the high-tungsten-nickel alloy target material.)

1. A preparation method of a tungsten-nickel alloy target is characterized by comprising the following steps: the preparation method comprises the following preparation steps:

selecting multi-element alloy powder consisting of tungsten powder, nickel powder and other metal powder as a raw material of a tungsten-nickel alloy target, and sieving the raw material for later use;

secondly, putting the alloy powder selected in the step one into a die, and preparing a powdery blank or a powdery tube blank through cold isostatic pressing;

step three, putting the powder blank or the powder tube blank into a sintering furnace, and sintering in a hydrogen or vacuum environment to obtain a sintered blank with the density of more than 98 percent for later use;

step four, heating the sintered blank at the temperature of 1000-1420 ℃ for 60-90 min, forging the sintered blank by matching with a corresponding forging die, forging the sintered blank twice according to the designed forging die, forging the outer diameter of the sintered blank with a part of length to the specification required by the target size for the first time, then performing annealing compensation heating for 60-90 min, forging the outer diameter of the sintered blank with the rest length to the specification required by the target size, and finally forging the sintered blank with the reduction of section of 5-50% to prepare a forged blank for later use;

step five, annealing the forged blank obtained in the step four at the annealing temperature of 800-1300 ℃ for 1-5 h, and then cooling for later use;

step six, machining the blank processed in the step five to a target required size, and then carrying out defect detection and crystal scanning detection;

and seventhly, washing the qualified product subjected to nondestructive testing in the sixth step by using clean water, drying and then carrying out vacuum packaging to obtain a finished product.

2. The method for preparing a tungsten-nickel alloy target according to claim 1, wherein the method comprises the following steps: the grain size of the alloy powder screened in the first step is 160-500 meshes.

3. The method for preparing a tungsten-nickel alloy target according to claim 1, wherein the method comprises the following steps: the other metal powder in step one includes but is not limited to Al, Ti, Cu, Co.

4. The method for preparing a tungsten-nickel alloy target according to claim 1, wherein the method comprises the following steps: the multi-element alloy powder in the first step comprises the following components in parts by mass: 10-90 parts of tungsten powder and 10-90 parts of nickel powder.

5. The method for preparing the tungsten-nickel alloy target material according to claim 3, wherein the method comprises the following steps: the multi-element alloy powder in the step one is composed of any one or more of tungsten powder, nickel powder and other metal powder.

6. The method for preparing the tungsten-nickel alloy target material according to claim 5, wherein the method comprises the following steps: according to the mass parts, 10-90 parts of tungsten powder, 10-90 parts of nickel powder and less than 10 parts of other metal powder are contained in the multi-component alloy powder.

7. The method for preparing a tungsten-nickel alloy target according to claim 1, wherein the method comprises the following steps: in the first step, the multi-component alloy powder is primarily mixed by adopting a sieving and mixing mode before mixing, and then the multi-component alloy powder is placed in a vacuum stirrer to be uniformly stirred.

8. The method for preparing a tungsten-nickel alloy target according to claim 1, wherein the method comprises the following steps: and the mould in the second step is a tubular flexible mould, the pressing pressure of the cold isostatic pressing is 150-280 MPa, and the pressure maintaining time is 10-30 min.

9. The method for preparing a tungsten-nickel alloy target according to claim 1, wherein the method comprises the following steps: in the third step, the sintering temperature is 800-1453 ℃, and the sintering time is 6-48 h.

10. The method for preparing a tungsten-nickel alloy target according to claim 1, wherein the method comprises the following steps: and step six, water immersion type ultrasonic C scanning is used, no pore defect with the average diameter larger than 0.3mm exists in the machined tube blank, the wave intensity of the bottom surface of crystal scanning is not smaller than 80%, and the average grain diameter is smaller than 35 um.

Technical Field

The invention belongs to the technical field of alloy sputtering target processing, and particularly relates to a preparation method of a tungsten-nickel alloy target material.

Background

The electrochromic intelligent glass has adjustability of light absorption and transmission under the action of an electric field, can selectively absorb or reflect external heat radiation and internal heat diffusion, and the optical performance (reflectivity, transmissivity and absorptivity) of the material is reversibly changed, so that the electrochromic intelligent glass is a development direction of energy-saving building materials. At present, electrochromic intelligent glass is applied to some high-grade cars and airplanes, and is widely applied to the fields of intelligent windows, anti-dazzling reflectors, optical information storage and the like. As the basis of the preparation of electrochromic glass films, tungsten-nickel alloy sputtering coating targets are widely used, and during coating, the tungsten-nickel alloy targets generate tungsten-nickel alloy oxide layers on the surfaces of glass, and undergo redox reaction under the action of voltage to change the color.

However, most of currently applied tungsten-nickel targets are manufactured by a thermal spraying process, the density of the sputtering target is only about 90%, nickel elements in the target are not uniformly distributed, and the sputtering performance of the product is influenced, so that the quality of an electrochromic layer is influenced. Therefore, the development of the tungsten-nickel alloy sputtering target material with high density, uniform microstructure and consistent grain orientation becomes the key for preparing high-performance electrochromic glass at present.

Disclosure of Invention

In order to overcome a series of problems of low density, uneven structure and the like of a tungsten-nickel alloy target material in the process of preparing the tungsten-nickel alloy target material by the existing thermal spraying process, the invention provides a preparation method of the tungsten-nickel alloy target material, which adopts a powder metallurgy method and adopts low-temperature sintering and forging processes to prepare a high-performance tungsten-nickel alloy sputtering target material with the density approaching or equal to theoretical density, the average grain size less than or equal to 35 mu m, uniform structure and consistent grain orientation.

The technical scheme adopted by the invention for solving the technical problems is as follows: a preparation method of a tungsten-nickel alloy target comprises the following preparation steps:

selecting multi-element alloy powder consisting of tungsten powder, nickel powder and other metal powder as a raw material of a tungsten-nickel alloy target, and sieving the raw material for later use;

secondly, putting the alloy powder selected in the step one into a die, and preparing a powdery blank or a powdery tube blank through cold isostatic pressing;

step three, putting the powder blank or the powder tube blank into a sintering furnace, and sintering in a hydrogen or vacuum environment to obtain a sintered blank with the density of more than 98 percent for later use;

step four, heating the sintered blank at the temperature of 1000-1420 ℃ for 60-90 min, forging the sintered blank by matching with a corresponding forging die, forging the sintered blank twice according to the designed forging die, forging the outer diameter of the sintered blank with a part of length to the specification required by the target size for the first time, then performing annealing compensation heating for 60-90 min, forging the outer diameter of the sintered blank with the rest length to the specification required by the target size, and finally forging the sintered blank with the reduction of section of 5-50% to prepare a forged blank for later use;

step five, annealing the forged blank obtained in the step four at the annealing temperature of 800-1300 ℃ for 1-5 h, and then cooling for later use;

step six, machining the blank processed in the step five to a target required size, and then carrying out defect detection and crystal scanning detection;

step seven, washing the qualified product subjected to nondestructive inspection in the step six by using clean water, drying and then carrying out vacuum packaging to obtain a finished product;

further, the grain diameter of the alloy powder screened in the first step is 160-500 meshes.

Further, the other metal powder in the first step includes, but is not limited to, Al, Ti, Cu, Co.

Further, the multi-element alloy powder in the first step comprises the following components in parts by mass: 10-90 parts of tungsten powder and 10-90 parts of nickel powder.

Further, the multi-component alloy powder in the step one is composed of any one or more of tungsten powder, nickel powder and other metal powder.

Further, the multi-component alloy powder comprises, by mass, 10-90 parts of tungsten powder, 10-90 parts of nickel powder and less than 10 parts of other metal powder.

Further, in the first step, the multi-component alloy powder is primarily mixed by adopting a sieving and mixing mode before mixing, and then the multi-component alloy powder is placed in a vacuum stirrer to be uniformly stirred.

Further, the die in the second step is a tubular flexible die, the pressing pressure of cold isostatic pressing is 150-280 MPa, and the pressure maintaining time is 10-30 min.

Furthermore, in the third step, the sintering temperature is 800-1453 ℃, and the sintering time is 6-48 h.

Furthermore, in the sixth step, water immersion type ultrasonic C scanning is used, no pore defect with the average diameter larger than 0.3mm exists in the machined tube blank, the wave intensity of the bottom surface of crystal scanning is not smaller than 80%, and the average grain diameter is smaller than 35 um.

The invention has the beneficial effects that: the invention adopts a powder metallurgy method, and prepares the high-performance tungsten-nickel alloy sputtering target material with the density close to or equal to the theoretical density, the average grain size less than or equal to 35um, uniform tissue and consistent grain orientation by low-temperature sintering and forging processes, overcomes the limitations of low density, nonuniform tissue and the like of the tungsten-nickel alloy sputtering target material prepared by the traditional thermal spraying process, and lays a solid practical foundation for the development and application of electrochromic glass.

Detailed Description

The embodiments of the present invention are described in detail with reference to specific embodiments, and the embodiments and specific operations are provided in the present embodiment on the premise of the technical solution of the present invention, but the scope of the present invention is not limited to the following embodiments.

A preparation method of a tungsten-nickel alloy target comprises the following preparation steps:

selecting multi-element alloy powder consisting of tungsten powder, nickel powder and other metal powder as a raw material of a tungsten-nickel alloy target, and sieving the raw material for later use;

secondly, putting the alloy powder selected in the step one into a die, and preparing a powdery blank or a powdery tube blank through cold isostatic pressing;

step three, putting the powder blank or the powder tube blank into a sintering furnace, and sintering in a hydrogen or vacuum environment to obtain a sintered blank with the density of more than 98 percent for later use;

step four, heating the sintered blank at the temperature of 1000-1420 ℃ for 60-90 min, forging the sintered blank by matching with a corresponding forging die, forging the sintered blank twice according to the designed forging die, forging the outer diameter of the sintered blank with a part of length to the specification required by the target size for the first time, then performing annealing compensation heating for 60-90 min, forging the outer diameter of the sintered blank with the rest length to the specification required by the target size, and finally forging the sintered blank with the reduction of section of 5-50% to prepare a forged blank for later use;

step five, annealing the forged blank obtained in the step four at the annealing temperature of 800-1300 ℃ for 1-5 h, and then cooling for later use;

step six, machining the blank processed in the step five to a target required size, and then carrying out defect detection and crystal scanning detection;

step seven, washing the qualified product subjected to nondestructive inspection in the step six by using clean water, drying and then carrying out vacuum packaging to obtain a finished product;

further, the grain diameter of the alloy powder screened in the first step is 160-500 meshes.

Further, the other metal powder in the first step includes, but is not limited to, Al, Ti, Cu, Co.

Further, the multi-element alloy powder in the first step comprises the following components in parts by mass: 10-90 parts of tungsten powder and 10-90 parts of nickel powder.

Further, the multi-component alloy powder in the step one is composed of any one or more of tungsten powder, nickel powder and other metal powder.

Further, the multi-component alloy powder comprises, by mass, 10-90 parts of tungsten powder, 10-90 parts of nickel powder and less than 10 parts of other metal powder.

Further, in the first step, the multi-component alloy powder is primarily mixed by adopting a sieving and mixing mode before mixing, and then the multi-component alloy powder is placed in a vacuum stirrer to be uniformly stirred.

Further, the die in the second step is a tubular flexible die, the pressing pressure of cold isostatic pressing is 150-280 MPa, and the pressure maintaining time is 10-30 min.

Furthermore, in the third step, the sintering temperature is 800-1453 ℃, and the sintering time is 6-48 h.

Furthermore, in the sixth step, water immersion type ultrasonic C scanning is used, no pore defect with the average diameter larger than 0.3mm exists in the machined tube blank, the wave intensity of the bottom surface of crystal scanning is not smaller than 80%, and the average grain diameter is smaller than 35 um.

A preparation method of a tungsten-nickel alloy target comprises the following steps:

firstly, selecting raw materials prepared from a tungsten-nickel alloy sputtering target material, wherein the raw materials comprise the following two materials: a. alloy powder consisting of tungsten powder and nickel powder; b. the tungsten powder, the nickel powder and one or more of other metal powders, for example, the tungsten powder, the nickel powder and one or more of metal powders of Al, Ti, Cu and Co form a multi-component alloy powder, it is particularly noted that the component defined in b is calculated according to the mass portion, the tungsten powder needs to be 10-90 parts, the nickel powder needs to be 90-10 parts, and the other metal element powder is controlled within 10 parts. When the selected powder raw materials are screened, a screen is selected to be 160-500 meshes, oversize materials are treated as waste materials, and undersize powder is reserved; before and after use, whether the screen is damaged or not is checked to ensure that sundries or large powder aggregates are screened out;

step two, the powder raw material selected in the step one is filled into a common flexible die or a tubular flexible die with a flexible steel core, the pressing pressure of cold isostatic pressing is 150-280 MPa, the pressure maintaining time is 10-30 min, and the specific execution process is adjusted within the range according to the specification of the prepared tungsten-nickel alloy sputtering target material and the technical indexes of the selected powder; cold isostatic pressing is used for automatically boosting the pressure of equipment, the boosting speed is not limited, and powder blanks are prepared by the cold isostatic pressing process;

step three, putting the powder blank into a sintering furnace, and sintering in a hydrogen or vacuum environment to obtain a sintered blank with the density of more than 98%, wherein the sintering temperature is 800-1453 ℃, and the sintering time is 6-48 h;

step four, heating the sintered blank in a muffle furnace at the heating temperature of 1000-1420 ℃, specifically selecting the sintered blank according to the designed material and the forging deformation of the product, wherein the heating time is 60-90 min, the specification of the selected die is the target dimension requirement, forging and processing are carried out twice according to the designed forging die, the outer diameter dimension of the sintered blank with a part of length is forged to the specification of the target dimension requirement for the first time, then the sintered blank with the rest length is forged to the specification of the target dimension requirement after the sintered blank is returned to the furnace for compensation heating for 60 min-90 min, and finally the reduction of section of forging is 5-50%, so that the forged blank is prepared;

step five, annealing the forged blank at the annealing temperature of 800-1300 ℃ for 1-5 h to optimize the metallographic structure of the forged blank, refine crystal grains, promote the processed structure to change to a recovery structure, enable the metallographic structure in the blank to tend to a stable state, further improve the comprehensive mechanical properties, and then cool for later use;

and step six, machining the blank subjected to heat treatment to a target required size, scanning by using water immersion type ultrasonic C, wherein no pore defect with the average diameter larger than 0.3mm exists in the machined tube blank, the intensity of the bottom surface wave of crystal scanning is not smaller than 80%, and the average grain diameter is smaller than 35 microns. The water immersion type ultrasonic C scanning is divided into two times, different models are respectively selected to detect physical defects and grain structure uniformity, and the detection result is expressed by color difference of color pictures;

and seventhly, washing the machined target body with clean water, drying and then carrying out vacuum packaging to obtain the tungsten-nickel alloy sputtering target material.

Example 1

A preparation method of a tungsten-nickel alloy target comprises the following steps:

selecting tungsten powder and nickel powder, wherein the Fisher size of the tungsten powder and the nickel powder is 3.0 mu m, the tungsten powder and the nickel powder in batches need to be sampled and analyzed, various physical and chemical performance indexes meet application requirements, screening the tungsten powder and the nickel powder by using a 500-mesh screen, treating oversize materials as waste materials, and reserving the tungsten powder and the nickel powder under the screen, wherein the mixing ratio of the tungsten powder to the nickel powder is as follows according to the mass fraction: 10% and 90%;

selecting a tube-shaped rubber mold with the specification of phi 200 multiplied by phi 100 multiplied by 400mm, cleaning the interior, matching with a phi 90mm flexible steel core, uniformly adding tungsten-nickel alloy mixed powder, and loading the powder with the weight of 90 kg; after sealing, cold isostatic pressing is carried out, the pressing pressure is 180MPa, and the pressure maintaining time is 20 min; demolding for later use after pressing is finished;

step three, putting the powdery pipe blank into a medium-frequency induction sintering furnace, introducing hydrogen as a protective and reducing atmosphere, sintering at 900 ℃ for 48 hours, cooling along with the furnace, discharging, and measuring the sintering density to 8.939g/cm³；

Step four, putting the sintered pipe blank into a muffle furnace with a hydrogen protective atmosphere for heating at 1420 ℃, keeping the temperature for 60min, selecting a die with the specification of phi 180 mm-phi 160mm, carrying out hollow forging treatment on the pipe blank, and straightening bending deformation of the pipe blank caused by the sintering process;

step five, carrying out 1220 ℃ recrystallization annealing by using an annealing furnace, preserving heat for 2 hours, and naturally cooling;

machining the tungsten-nickel tube blank subjected to heat treatment to the size required by a customer drawing, and then carrying out defect flaw detection to detect whether the tube blank has defects such as cracks, pores and the like, wherein the tungsten-nickel tube blank has no pore defect with the average diameter larger than 0.3 mm;

step seven, washing the machined target tube with clean water, drying and then carrying out vacuum packaging to obtain the target tube with the density of 9.38g/cm³And the tungsten-nickel alloy rotary sputtering target with the average grain size of 28 mu m.

Example 2

A preparation method of a tungsten-nickel alloy target comprises the following steps:

selecting tungsten powder and nickel powder, wherein the Fisher size of the tungsten powder and the nickel powder is 3.5 mu m, the tungsten powder and the nickel powder in batches need to be sampled and analyzed, various physical and chemical performance indexes meet application requirements, screening the tungsten powder and the nickel powder by using a 500-mesh screen, treating oversize materials as waste materials, and reserving the tungsten powder and the nickel powder under the screen, wherein the mixing ratio of the tungsten powder to the nickel powder is as follows according to the mass fraction: 90% and 10%;

selecting a tube-shaped rubber mold with the specification of phi 180 multiplied by phi 120 multiplied by 360mm, cleaning the interior, matching with a phi 100mm flexible steel core, uniformly adding tungsten-nickel alloy mixed powder, and loading the powder with the weight of 95 kg; after sealing, cold isostatic pressing is carried out, the pressing pressure is 185MPa, and the pressure maintaining time is 30 min; demolding for later use after pressing is finished;

step three, putting the powdery pipe blank into a medium-frequency induction sintering furnace, introducing hydrogen as a protective and reducing atmosphere, sintering at the temperature of 1400 ℃ for 42h, cooling along with the furnace, discharging, and measuring the sintering density to be 16.42g/cm³；

Step four, putting the sintered pipe blank into a muffle furnace with a hydrogen protective atmosphere for heating at the temperature of 1320 ℃, keeping the temperature for 60min, selecting a die with the specification of phi 170 mm-phi 150mm, carrying out hollow forging treatment on the pipe blank, and straightening bending deformation of the pipe blank caused by the sintering process;

step five, carrying out recrystallization annealing at 1250 ℃ by using an annealing furnace, preserving heat for 2 hours, and naturally cooling;

machining the tungsten-nickel tube blank subjected to heat treatment to the size required by a customer drawing, and then carrying out defect flaw detection to detect whether the tube blank has defects such as cracks, pores and the like, wherein the tungsten-nickel tube blank has no pore defect with the average diameter larger than 0.3 mm;

seventhly, washing the machined target tube with clean water, drying and then carrying out vacuum packaging to obtain the target tube with the density of 17.28g/cm³And the tungsten-nickel alloy rotary sputtering target material with the average grain size of 33 um.

Example 3

A preparation method of a tungsten-nickel alloy target comprises the following steps:

selecting tungsten powder and nickel powder, wherein the Fisher size of the tungsten powder and the nickel powder is 3.2 mu m, the tungsten powder and the nickel powder in batches need to be sampled and analyzed, various physical and chemical performance indexes meet application requirements, screening the tungsten powder and the nickel powder by using a 500-mesh screen, treating oversize materials as waste materials, and reserving the tungsten powder and the nickel powder under the screen, wherein the mixing ratio of the tungsten powder to the nickel powder is as follows according to the mass fraction: 80% and 20%;

selecting a rectangular rubber mold with the specification of 50 multiplied by 150 multiplied by 400mm, cleaning the interior of the rectangular rubber mold, uniformly adding tungsten-nickel alloy mixed powder, and filling the powder with the weight of 50 kg; after sealing, cold isostatic pressing is carried out, the pressing pressure is 160MPa, and the pressure maintaining time is 20 min; demolding for later use after pressing is finished;

step three, putting the powdery slab into a medium-frequency induction sintering furnace, introducing hydrogen as a protective and reducing atmosphere, sintering at 1350 ℃ for 40h, cooling along with the furnace, discharging, and measuring the sintering density to be 15.33g/cm³；

Step four, putting the sintered plate blank into a muffle furnace with a hydrogen protective atmosphere for heating, wherein the heating temperature is 1350 ℃, the heat preservation time is 60min, and forging the sintered plate blank;

step five, carrying out recrystallization annealing at 1200 ℃ by using an annealing furnace, preserving heat for 2 hours, and naturally cooling;

machining the tungsten-nickel plate blank subjected to heat treatment to the size required by a customer drawing, and then carrying out defect flaw detection to detect whether flaws such as cracks, pores and the like exist in the tube blank, wherein the inner part of the tube blank of the tungsten-nickel tube blank has no pore defects with the average diameter larger than 0.3 mm;

step seven, washing the machined plate blank by using clean water, drying and then carrying out vacuum packaging to obtain the plate blank with the density of 15.65g/cm³And the average grain size of the tungsten-nickel alloy rotary sputtering target material is 31 um.

Example 4

A preparation method of a tungsten-nickel alloy target comprises the following steps:

selecting tungsten powder and nickel powder, wherein the Fisher size of the tungsten powder and the nickel powder is 3.2 mu m, the Fisher size of the copper powder is 2.0 mu m, the tungsten powder, the nickel powder and the copper powder in batches need to be sampled and analyzed, various physical and chemical performance indexes meet application requirements, screening with a 500-mesh screen, treating oversize materials as waste materials, and reserving the tungsten powder, the nickel powder and the copper powder under the screen, wherein the mixing ratio of the tungsten powder, the nickel powder and the copper powder is respectively as follows according to the mass fraction: 72.5%, 21%, 6.5%;

selecting a rectangular rubber mold with the specification of 40 multiplied by 200 multiplied by 400mm, cleaning the interior of the rectangular rubber mold, uniformly adding tungsten-nickel-copper alloy mixed powder, and filling the powder with the weight of 50 kg; after sealing, cold isostatic pressing is carried out, the pressing pressure is 190MPa, and the pressure maintaining time is 30 min; demolding for later use after pressing is finished;

step three, putting the powdery slab into a medium-frequency induction sintering furnace, introducing hydrogen as a protective and reducing atmosphere, sintering at 1280 ℃ for 38 hours, cooling along with the furnace, discharging, and measuring the sintering density to be 14.33g/cm³；

Step four, putting the sintered plate blank into a muffle furnace with a hydrogen protective atmosphere for heating, wherein the heating temperature is 1250 ℃, the heat preservation time is 90min, and forging the sintered plate blank;

step five, carrying out recrystallization annealing at 1150 ℃ by using an annealing furnace, preserving heat for 2 hours, and naturally cooling;

machining the tungsten-nickel copper plate blank subjected to heat treatment to the size required by a customer drawing, and then performing defect flaw detection to detect whether defects such as cracks, pores and the like exist in the tungsten-nickel copper plate blank or not, wherein no pore defect with the average diameter larger than 0.3mm exists in the tungsten-nickel copper plate blank;

step seven, flushing the machined tungsten-nickel copper plate blank with clean water, drying and then carrying out vacuum packaging to obtain the tungsten-nickel copper plate blank with the density of 14.62g/cm³And the average grain size is 25 um.

The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

It should be noted that while the invention has been described in terms of the above-mentioned embodiments, other embodiments are also possible. It will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention, and it is intended that all such changes and modifications be covered by the appended claims and their equivalents.