WO2016169349A1

WO2016169349A1 - Scroll compressor and driving shaft and unloading bush for scroll compressor

Info

Publication number: WO2016169349A1
Application number: PCT/CN2016/075986
Authority: WO
Inventors: 周光勇; 束宏飞; 李庆伟; 王石; 过炜华
Original assignee: 艾默生环境优化技术(苏州)有限公司
Priority date: 2015-04-23
Filing date: 2016-03-09
Publication date: 2016-10-27
Also published as: JP2018517097A; EP3287638A1; EP3287638A4; KR20170138506A

Abstract

A scroll compressor comprises a compressing mechanism (10) for compressing working fluid and a driving shaft (30) for driving the compressing mechanism (10). The driving shaft (30) comprises an eccentric crank pin (32). An unloading bush (42) is arranged between the compressing mechanism (10) and the eccentric crank pin (32), so that the eccentric crank pin (32) drives the compressing mechanism (10) via the unloading bush (42) to realize radial flexibility of the compressing mechanism (10). The eccentric crank pin (32) comprises an eccentric crank pin matching part which is in contact with the unloading bush (42) and relatively displaces. The unloading bush (42) comprises an unloading bush matching part which is in contact with the eccentric crank pin (32) and relatively displaces. A wear resisting layer (50) is arranged on at least one part of at least one of the eccentric crank pin matching part and the unloading bush matching part. An unloading bush provided with a wear resisting layer for a scroll compressor and a driving shaft with an eccentric crank pin provided with the wear resisting layer. Because of the arrangement of the wear resisting layer, the service life of the scroll compressor is prolonged.

Description

Scroll compressor and drive shaft and unloading bushing for scroll compressor

The present application claims the priority of the Chinese Patent Application, filed on Apr. 23, 2015, the disclosure of which is hereby incorporated by reference.

Technical field

The present invention relates to a scroll compressor and a drive shaft and an unloading bushing for a scroll compressor.

Background technique

The content of this section merely provides background information related to the present disclosure, which may not constitute prior art.

A scroll compressor typically has a compression mechanism that compresses a working fluid (eg, a refrigerant) including a fixed scroll component and an orbiting scroll component. The compression mechanism is driven by an eccentric crank pin of the drive shaft. An unloading bushing is disposed between the eccentric crank pin and the compression mechanism. The unloading bushing is configured to be drivable by the eccentric crank pin and to be relatively displaceable relative to the eccentric crank pin, whereby radial flexibility between the fixed scroll member and the blades of the orbiting scroll member can be achieved.

However, the relative movement between the unloading bushing and the eccentric crank pin causes their contact faces to wear rapidly, thereby affecting the radial flexibility of the compressor and shortening the service life of the unloading bushing and the eccentric crank pin.

Therefore, there is a need for a wear resistant unloading bushing and eccentric crank pin for use in a scroll compressor.

Summary of the invention

It is an object of the present invention to provide a scroll compressor having a wear resistant unloading bushing and/or an eccentric crank pin.

Another object of the present invention is to provide a scroll compressor having a long service life.

Another object of the present invention is to provide a wear resistant unloading bushing.

Another object of the present invention is to provide a drive shaft having a wear resistant eccentric crank pin.

According to an aspect of the invention, a scroll compressor is provided, comprising: a compression mechanism configured to compress a working fluid; and a drive shaft configured to drive the compression mechanism. The drive shaft includes an eccentric crank pin with an unloading bushing disposed between the compression mechanism and the eccentric crank pin such that the eccentric crank pin drives the compression mechanism via the unloading bushing to achieve radial flexibility of the compression mechanism. The eccentric crank pin includes an eccentric crank pin engagement portion that contacts and is displaced relative to the unloading bushing, the unloading bushing including an unloading bushing mating portion that contacts and is displaced relative to the eccentric crank pin. A wear layer is disposed on at least a portion of at least one of the eccentric crank pin engagement portion and the unloading bushing engagement portion.

In the above scroll compressor, since the wear portion is provided on the fitting portion of the eccentric crank pin or the unloading bush, the wear resistance of the eccentric crank pin or the unload bush bush is improved, and the eccentric crank pin or the unload bush bush is extended. The service life. As a result, the life of the scroll compressor having the eccentric crank pin and the unloading bush is prolonged.

Preferably, the eccentric crank pin includes a drive face extending parallel to the axis of rotation of the drive shaft, the eccentric crank pin mating portion including at least a portion of the drive face.

Preferably, a wear resistant layer is provided on at least a portion located substantially at the center of the driving surface and convex outward.

Preferably, the unloading bushing may include a bore capable of receiving an eccentric crank pin having a driven face that cooperates with a drive face of the eccentric crank pin, the unloading bushing mating portion including at least a portion of the driven face.

Preferably, a wear resistant layer is provided on at least a portion of the substantially central portion of the driven surface.

Preferably, the wear resistant layer is a hardened layer having a surface hardness in the range of 1500 HV to 3000 HV.

Preferably, the thickness of the wear resistant layer is in the range of from 0.1 micron to 4.5 microns.

Preferably, the wear resistant layer is formed by one of the following methods: physical vapor deposition, chemical vapor deposition, plasma vapor deposition, electroplating, electroless plating, carburizing, nitriding, carbonitriding, shot peening, and surface hardening heat treatment.

Preferably, the wear resistant layer is formed from one of the following materials: a metal layer, a diamond-like, a carbide, a nitride, a silicide, a boride, and an oxide. Optionally, the wear resistant layer is formed from chromium nitride.

According to another aspect of the present invention, a drive shaft for a scroll compressor, wherein the drive shaft includes an eccentric crank pin disposed at one end thereof for driving a compression mechanism of the scroll compressor, the eccentric crank The pin includes a drive surface that extends parallel to the axis of rotation of the drive shaft. A wear layer is disposed on at least a portion of the driving surface substantially convex and outwardly, and the wear layer is formed by physical vapor deposition, chemical vapor deposition, plasma vapor deposition, electroplating, electroless plating, carburizing, nitriding, A hardened layer comprising a metal layer, a diamond-like layer, a carbide, a nitride, a silicide, a boride or an oxide formed by carbonitriding, shot peening or surface hardening heat treatment.

According to another aspect of the present invention, an unloading bushing for a scroll compressor, wherein the unloading bushing includes a hole having a substantially D shape having a driving surface with an eccentric crank pin of a scroll compressor The driven surface of the fit. At least in the substantially central portion of the driven surface is provided with a wear-resistant layer by physical vapor deposition, chemical vapor deposition, plasma vapor deposition, electroplating, electroless plating, carburizing, nitriding, carbonitriding A hardened layer comprising a metal layer, a diamond-like layer, a carbide, a nitride, a silicide, a boride or an oxide formed by shot peening or surface hardening heat treatment.

DRAWINGS

The features and advantages of one or more embodiments of the present invention will become more <RTIgt;

Figure 1 is a longitudinal sectional view of a scroll compressor;

Figure 2 is a schematic view showing the assembly of the eccentric crank pin and the unloading bushing of the drive shaft of the scroll compressor of Figure 1;

Figure 3 is a perspective view showing the eccentric crank pin of the drive shaft of Figure 2;

Figure 4 shows a perspective view of the unloading bushing of Figure 2;

FIG. 5 schematically illustrates a method of forming an abrasion resistant layer in accordance with a first embodiment of the present invention;

Figure 6 is a schematic illustration of a wear resistant layer.

detailed description

The following description of the preferred embodiments is merely exemplary and is in no way limiting The same reference numerals are used in the respective drawings to refer to the same components, and thus the construction of the same components will not be repeatedly described.

The overall configuration and operating principle of the scroll compressor will first be described with reference to FIG. 1 shows a high pressure side compressor, however, it should be understood that the high pressure side compressor of FIG. 1 is for illustrative purposes only and is not limiting of the invention. The invention may be adapted to any type of compressor, including low pressure side compressors, vertical compressors, horizontal compressors, and the like.

As shown in FIG. 1, a scroll compressor 100 (hereinafter sometimes referred to as a compressor) generally includes a housing 110, a top cover 112 disposed at one end of the housing 110, and a bottom cover 114 disposed at the other end of the housing 110. . A motor 20 composed of a stator 122 and a rotor 124 is disposed in the housing 110. A drive shaft 30 is provided in the rotor 124 to drive the compression mechanism 10 constituted by the fixed scroll member 150 and the movable scroll member 160. The movable scroll member 160 includes an end plate 164, a hub portion 162 formed on one side of the end plate, and a spiral blade 166 formed on the other side of the end plate. The fixed scroll member 150 includes an end plate 154, a spiral blade 156 formed on one side of the end plate, and an exhaust port 152 formed at a substantially central position of the end plate. A series of compression chambers whose volume gradually decreases from the radially outer side to the radially inner side are formed between the spiral vanes 156 of the fixed scroll member 150 and the spiral vanes 166 of the orbiting scroll member 160. Wherein, the radially outermost compression chamber is at the suction pressure, and the radially innermost compression chamber is at the exhaust pressure. The intermediate compression chamber is between the suction pressure and the discharge pressure, and is also referred to as the medium pressure chamber.

One side of the movable scroll member 160 is supported by an upper portion of the main bearing housing 140 (which constitutes a thrust surface), and a portion of the drive shaft 30 is supported by a main bearing provided in the main bearing housing 140. One end of the drive shaft 30 is provided with an eccentric crank pin 32, and an unloading bushing 42 is disposed between the eccentric crank pin 32 and the hub portion 162 of the movable scroll member 160. By the driving of the motor 20, the orbiting scroll member 160 will rotate rotationally relative to the fixed scroll member 150 (i.e., the central axis of the orbiting scroll member 160 is rotated about the central axis of the scroll member 150, but the orbiting scroll member 160 is rotated. It does not rotate itself around its central axis to achieve compression of the fluid. The translational rotation described above is achieved by a cross slip ring disposed between the fixed scroll member 150 and the movable scroll member 160.

In the example of the scroll compressor shown in Fig. 1, a lubricant is stored at the bottom of the compressor housing. Accordingly, a passage extending substantially in the axial direction thereof is formed in the drive shaft 30, that is, a center hole 136 formed at the lower end of the drive shaft 30 and an eccentric hole 134 extending upward from the center hole 136 to the end surface of the eccentric crank pin 32. The end of the central bore 136 is submerged in the lubricant at the bottom of the compressor housing or otherwise supplied with a lubricant. During operation of the compressor, one end of the center hole 136 is supplied with lubricant by the lubricant supply means, and the lubricant entering the center hole 136 is pumped or plucked to the eccentric hole by the centrifugal force during the rotation of the drive shaft 30. The 134 and the upward flow along the eccentric hole 134 continue until reaching the end surface of the eccentric crank pin 32. Lubricant discharged from the end face of the eccentric crank pin 32 along the gap between the unloading bushing 42 and the eccentric crank pin 32 and the unloading bushing The gap between the 42 and the hub 162 flows downward into the recess of the main bearing housing 140. A portion of the lubricant collected in the recess flows downward through the main bearing, and a portion of the lubricant is agitated by the hub 162 to move upward to the lower side of the end plate 164 of the orbiting scroll member 160 and follow the movable scroll member 160. The translation is rotated to extend over the thrust surface of the orbiting scroll member 160 and the main bearing housing 140. During operation of the compressor, the lubricant supplied to the various moving parts in the compressor is scooped and splashed to form droplets or mist.

In the scroll compressor shown in Fig. 1, in order to achieve compression of the fluid, it is necessary to effectively seal between the fixed scroll member 150 and the orbiting scroll member 160. In one aspect, between the tip end of the helical blade 156 of the fixed scroll member 150 and the end plate 164 of the movable scroll member 160 and between the tip end of the helical blade 166 of the orbiting scroll member 160 and the end plate 154 of the fixed scroll member 150. An axial seal is required. The axial flexibility of the scroll compressor is well known to those skilled in the art and will therefore not be described in detail herein.

On the other hand, a radial seal is also required between the side surface of the spiral blade 156 of the fixed scroll member 150 and the side surface of the spiral blade 166 of the movable scroll member 160. This radial sealing between the two is typically achieved by means of the relative displacement between the eccentric crank pin 32 and the unloading bushing 42. Specifically, during operation, by the driving of the motor 20, the orbiting scroll member 160 will rotate in translation with respect to the fixed scroll member 150, so that the orbiting scroll member 160 will generate centrifugal force. On the other hand, the eccentric crank pin 32 of the drive shaft 30 also generates a driving force component that contributes to the radial sealing of the fixed scroll member 150 and the movable scroll member 160 during the rotation. The helical vanes 166 of the orbiting scroll member 160 will abut against the helical vanes 156 of the fixed scroll member 150 by means of the above-described centrifugal and driving force components, thereby achieving a radial seal therebetween. When an incompressible substance such as solid impurities, lubricating oil, and liquid refrigerant enters the compression chamber and is caught between the spiral blade 156 and the spiral blade 166, the spiral blade 156 and the spiral blade 166 can be temporarily separated from each other in the radial direction to allow The foreign matter passes, that is, a relative displacement is generated between the eccentric crank pin 32 and the unloading bushing 42, thus preventing the

spiral blade

156 or 166 from being damaged. This ability to be radially separated provides radial flexibility to the scroll compressor, increasing compressor reliability.

However, the relative displacement between the eccentric crank pin 32 and the unloading bushing 42 causes them to be too fast and excessively worn. In order to solve this problem, in the present invention, the wear-resistant layer of the eccentric crank pin 32 and/or the unloading bushing 42 is coated with a wear-resistant layer to improve its hardness and wear resistance.

The eccentric crank pin and the unloading bushing will be described in detail below with reference to FIGS. 2 to 4.

As shown in Figure 3, a perspective view of the eccentric crank pin of the drive shaft is shown. Drive shaft One end of 30 includes an eccentric crank pin 32. An eccentric hole 134 is formed in the drive shaft 30 in a first direction (longitudinal direction) substantially parallel to the rotational axis of the drive shaft 30 to supply lubricant to the end of the eccentric crank pin 32. The eccentric crank pin 32 of the drive shaft 30 is fitted into the hub portion 162 of the orbiting scroll member 160 via the unloading bushing 42, as shown in FIG. The eccentric crank pin 32 includes a drive surface 321 that extends parallel to the axis of rotation of the drive shaft 30. Accordingly, the generally D-shaped aperture of the unloading bushing 42 through which the eccentric crank pin 32 passes includes a driven surface 143 that is engageable with the drive surface 321 of the eccentric crank pin 32. After the unloading bushing 42 and the eccentric crank pin 32 are assembled to the compressor 100, the size of the generally D-shaped hole in the unloading bushing 42 is larger than the size of the eccentric crank pin 32 to ensure the orbiting scroll member 160 and the fixed scroll member. Radial flexibility between 150.

As shown in Figure 2, it shows an assembled view of the unloading bushing and the eccentric crank pin. When the unloading bushing 42 is mounted to the eccentric crank pin 32, the eccentric crank pin 32 is received in the D-shaped hole of the unloading bushing 42 while the driving surface 321 of the eccentric crank pin 32 and the driven surface of the unloading bushing 42 143 fit. With this configuration, when the eccentric crank pin 32 rotates, since the driving surface 321 of the eccentric crank pin 32 is engaged with the driven surface 143 of the unloading bush 42, the eccentric crank pin 32 can drive the unloading bush 42 to rotate. In addition, the width of the driving surface 321 of the eccentric crank pin 32 (that is, the dimension perpendicular to the axial direction of the drive shaft) is smaller than the width of the driven surface 143 of the unloading bush 42 (that is, the dimension perpendicular to the axial direction of the drive shaft). . Thus, the driving surface 321 of the eccentric crank pin 32 can move relative to the driven surface 143 of the unloading bushing 42.

In the ideal operating conditions of the compressor and its ideal design and manufacturing dimensions (ie, no manufacturing and installation tolerances), the spiral vanes of the fixed scroll and the orbiting scroll can be tightly fitted when the compressor is running. Together. At this time, the distance between the center of the unloading bushing and the center of the drive shaft is the largest and substantially constant.

However, the inventors have found that the center-to-center distance of the fixed scroll member and the orbiting scroll member is not uniform due to manufacturing and installation errors, and therefore, after the compressor is operated for a period of time, an unloading bushing and an eccentric crank pin are generated. The relative displacement (which corresponds to manufacturing and mounting errors), in particular, the flatness of the unloading bushing. In addition, the inventors have also found that, under actual operating conditions, when encountering impurities or liquid refrigerant entering, the center of the movable scroll member can be toward the center of the drive shaft due to relative movement of the unloading bushing relative to the eccentric crank pin. Offset, so the spiral vanes of the fixed scroll and the orbiting scroll are temporarily separated to prevent damage.

During the actual operation of the compressor, both the driven surface 143 of the unloading bushing 42 and the driving surface 321 of the eccentric crank pin 32 are subjected to normal loads, and there is relative movement between the two driven

faces

143, 321 . Therefore, the driven surface 143 of the unloading bushing 42 and the driving surface 321 of the eccentric crank pin 32 are severely worn, thereby shortening the service life thereof and affecting the working efficiency of the compressor.

For this purpose, according to the invention, a wear-resistant layer (which may also be referred to as a "hardened coating" or a "hardened film") may be provided on the driven surface 143 of the unloading bushing 42 and/or the driving surface 321 of the eccentric crank pin 32. 50 to improve its wear resistance.

An example of the wear resistant layer and its process engineering according to the present invention will now be described with reference to Figs. 5 and 6.

As shown in FIG. 5, the substrate S to be coated (for example, the driven surface 143 of the unloading bushing 42 herein and/or the driving surface 321 of the eccentric crank pin 32) is housed in the chamber and Ground it or connect it to the negative supply while the target T (eg, a chromium target) is also housed in the chamber and connected to the positive supply. The chamber was evacuated while filling with nitrogen. The target material is ionized by nitrogen under the action of an arc generated by a low voltage and a large current, and is accelerated by the electric field to strike the workpiece to form a chromium nitride film layer attached to the surface of the substrate.

The above process is merely an example of physical vapor deposition and is not intended to limit the invention. The wear layer 50 of the present invention can be formed by other processes known in the art, for example, chemical vapor deposition, plasma vapor deposition, electroplating, electroless plating, carburizing, nitriding, carbonitriding, shot peening , surface quenching heat treatment, etc. The wear layer 50 may be formed of a metal layer, a diamond-like layer, a carbide, a nitride, a silicide, a boride or an oxide, etc. according to various processes. For example, the wear layer 50 may be formed of chromium nitride.

In the present invention, the eccentric crank pin 32 and/or the unloading bushing 42 may be made of a powder metallurgy material having a surface hardness in the range of approximately 600 HV to 800 HV. When the process according to FIGS. 5 and 6 is on the eccentric crank pin 32 and/or the unloading bushing 42 (eg, on the drive face 321 of the eccentric crank pin 32 and/or the driven face 143 of the unloading bushing 42 When coated with a chromium nitride wear resistant layer 50 of approximately 2 to 4 microns thick, the surface hardness of the chromium nitride wear resistant layer 50 may range from 1500 HV to 3000 HV, optionally ranging from 1700 HV to 2700 HV. Thereby, the surface hardness of the driving surface of the eccentric crank pin 32 and/or the driven surface of the unloading bushing 42 can be remarkably improved, and the wear resistance can be greatly enhanced. Additionally, the thickness of the wear layer 50 can range from 0.1 microns to 4.5 microns.

The inventors conducted reliability tests on the eccentric crank pin 32 and the unloading bushing 42 coated with the chromium nitride wear-resistant layer 50 described above. Specifically, the eccentric crank pin 32 and the unloading bushing 42 were mounted to the compressor, and the compressor was operated under high speed and heavy load conditions for 500 hours, and the driving surface of the eccentric crank pin 32 and the driven surface of the unloading bushing 42 were found. Almost no wear occurred.

The above test shows that the wear layer 50 can prevent the eccentric crank pin 32 and the unloading bushing after the wear layer 50 is applied to the driving surface of the eccentric crank pin 32 and/or the driven surface of the unloading bushing 42. The powder metallurgy material of 42 is in direct contact, thereby preventing the powder metallurgy material from falling off. Thus, the wear layer 50 greatly enhances the wear resistance of the eccentric crank pin 32 and/or the unloading bushing 42.

Further, in some cases, in order to allow the eccentric crank pin 32 and the unloading bushing 42 to be well fitted according to the form of movement thereof, the driving surface 321 of the eccentric crank pin 32 may have a slightly convex portion substantially at the center. The wear layer 50 may be provided only on a slightly convex portion at substantially the center of the driving surface 321 or substantially at the center of the driven surface 143. Alternatively, it may be provided on the entire driving surface 321 and/or the driven surface 143. In addition, in addition to the drive surface 321 and/or the driven surface 143, the wear-resistant layer may also be applied to other portions of the eccentric crank pin 32 and/or the unloading bushing 42 that are subject to wear.

It should be understood that the contour and/or the position of the wear layer 50 may be shaped as desired.

Various embodiments and variations of the present invention have been described in detail above, but those skilled in the art should understand that the invention is not limited to the specific embodiments and variations described above, but may include various other possible combinations and combinations.

Although the various embodiments of the present invention have been described in detail herein, it is understood that the invention The skilled person implements other variations and variants. All such variations and modifications are intended to fall within the scope of the invention. Moreover, all of the components described herein can be replaced by other technically equivalent components.

Claims

A scroll compressor (100) comprising:

a compression mechanism (10) configured to compress a working fluid;

a drive shaft (30), the drive shaft (30) being configured to be capable of driving the compression mechanism (10);

Wherein the drive shaft (30) includes an eccentric crank pin (32), and an unloading bushing (42) is disposed between the compression mechanism (10) and the eccentric crank pin (32) such that the eccentric crank A pin (32) drives the compression mechanism (10) via the unloading bushing (42) to achieve radial flexibility of the compression mechanism (10),

The eccentric crank pin (32) includes an eccentric crank pin engagement portion that contacts and is displaced relative to the unloading bushing (42), the unloading bushing (42) including a contact with the eccentric crank pin (32) and opposite Displacement of the unloading bushing mating portion, and

A wear layer (50) is disposed on at least a portion of at least one of the eccentric crank pin engagement portion and the unloading bushing engagement portion.
The scroll compressor (100) according to claim 1, wherein said eccentric crank pin (32) includes a driving surface (321) extending parallel to an axis of rotation of said drive shaft (30), said eccentric crank The pin mating portion includes at least a portion of the drive surface (321).
A scroll compressor (100) according to claim 2, wherein said wear layer (50) is provided at least at a portion located substantially at the center of said driving surface (321) and convex outward.
The scroll compressor (100) according to claim 2, wherein said unloading bushing (42) includes a hole capable of accommodating said eccentric crank pin (32), said hole having said eccentric crank pin ( 32) The driving surface (321) of the driving surface (321) cooperates with the driven surface (143), and the unloading bushing fitting portion includes at least a portion of the driven surface (143).
A scroll compressor (100) according to claim 4, wherein said wear layer (50) is provided at least at a substantially central portion of said driven surface (143).
The scroll compressor (100) according to any one of claims 1 to 5, wherein The wear resistant layer (50) is a hardened layer having a surface hardness in the range of 1500 HV to 3000 HV.
The scroll compressor (100) according to any one of claims 1 to 5, wherein the wear layer (50) has a thickness in the range of 0.1 μm to 4.5 μm.
The scroll compressor (100) according to any one of claims 1 to 5, wherein the wear layer (50) is formed by one of the following methods: physical vapor deposition, chemical vapor deposition, plasma vapor deposition , electroplating, electroless plating, carburizing, nitriding, carbonitriding, shot peening and surface quenching heat treatment.
The scroll compressor (100) according to any one of claims 1 to 5, wherein the wear layer (50) is formed of one of the following materials: a metal layer, a diamond-like, a carbide, a nitride, Silicides, borides, and oxides.
The scroll compressor (100) according to claim 9, wherein the wear layer (50) is formed of chromium nitride.
A drive shaft (30) for a scroll compressor (100), wherein the drive shaft (30) includes a compression mechanism disposed at one end thereof for driving the scroll compressor (100) 10) an eccentric crank pin (32), the eccentric crank pin (32) including a drive surface (321) extending parallel to an axis of rotation of the drive shaft (30), and

At least a portion of the driving surface (321) that is substantially central and outwardly convex is provided with a wear-resistant layer (50) for physical vapor deposition, chemical vapor deposition, plasma vapor phase Hardened layer of metal, diamond-like, carbide, nitride, silicide, boride or oxide formed by deposition, electroplating, electroless plating, carburizing, nitriding, carbonitriding, shot peening or surface hardening heat treatment .
An unloading bushing (42) for a scroll compressor (100), wherein the unloading bushing (42) includes a substantially D-shaped bore having the scroll compressor (100) a driving surface (321) of the eccentric crank pin (32) that cooperates with the driven surface (143), and

A wear layer (50) is disposed on at least a portion of the substantially central portion of the driven surface (143), The wear layer (50) is a metal layer formed by physical vapor deposition, chemical vapor deposition, plasma vapor deposition, electroplating, electroless plating, carburizing, nitriding, carbonitriding, shot blasting or surface hardening heat treatment. a hardened layer of diamond-like, carbide, nitride, silicide, boride or oxide.