CS254656B1 - A method for preparing a wear-resistant titanium carbide thin layer on an electrically conductive solid substrate - Google Patents

Abstract

The essence of the method for preparing a wear-resistant thin layer of titanium carbide on an electrically conductive solid substrate consists in that a solid electrically conductive substrate heated to a temperature greater than 300 °C is treated with a plasma formed by titanium vapor and an inert gas, usually argon, at a reduced pressure in the range of 10' 4 to 10 Pa, followed by subsequent treatment under a reduced pressure in the range of 10 " 2 to 10 Pa with a plasma formed by titanium vapor and a hydrocarbon, usually acetylene, or titanium vapor and a mixture of hydrocarbon and inert gas, with the hydrocarbon concentration continuously increasing in the range of ratios to titanium from 0.2 to 0.7 and thereafter in the range from 0.7 to 1.0.

Description

The invention relates to a process for preparing a hard abrasion-resistant thin layer based on titanium carbide on a solid electrically conductive substrate under vacuum in a plasma.

Nowadays there are a number of more modern methods and technological procedures such as chemical coating, magnetron spraying and ion cladding, in addition to the classical methods of hard abrasion-resistant layers, such as galvanic, plasma, thermal spraying and so on. The big disadvantage of these methods is in some cases lower hardness of prepared layers, insufficient adhesion to coated substrate, deterioration of microgeometry quality of final surface of treated substrate, eventually necessity of heating of substrate to temperature of 900 ° C to 1100 ° C, energy and material intensity and last but not least and undesirable effects on the environment. Reactive ion cladding and magnetron sputtering methods can now be used to form titanium carbide layers on high speed steels, structural and tool steels, sintered carbides, titanium and aluminum alloys, and the like at temperatures above 300 ° C. Due to the inhomogeneities of the surface properties of these substrates, in many cases there is an inadequate adhesion of the prepared layer to the substrate. This results in loss of utility properties of the prepared layer in the process of its use.

The above-mentioned drawbacks are overcome by a novel process for preparing a titanium carbide layer on a solid electrically conductive substrate of the invention, which is based on the electrically conductive substrate heated to a temperature greater than 300 ° C by plating titanium and inert gas vapor, usually argon , under reduced pressure in the range 10 ^"4 Pa to thereby subsequently treated under reduced pressure in the range ^{of -2} to IC 10 Pa, the plasma formed by titanium vapor and a hydrocarbon, usually acetylene or para titanium and mixtures of hydrocarbon and inert gas, wherein the concentration of The hydrocarbon continuously increases in the ratio of titanium to from 0.2 to 0.7, and thereafter in the range of from 0.7 to 1.0.

It is further preferred according to the invention that the surface of the solid electrically conductive substrate be bombarded with inert gas ions, which causes the adsorbed layers to be dusted off its surface and at the same time to heat the substrate to the desired temperature.

The titanium carbide layers prepared according to the invention are characterized by the desired adhesion to the coated substrate, which is given by the titanium undercoat, high hardness and abrasion resistance. Because of these properties, the layers prepared according to the invention are predestined for applications, in particular in mechanical engineering, for cutting and forming tools, extremely stressed tribological nodes of machinery and the like. Examples of design

Example 1

Verification of the method according to the invention was carried out on a high-speed steel support ČSN 19 830, which was placed as a cathode in an ion cladding device with an electron source evaporator. The pads were heated to a temperature above 400 ° C during their purification in a argon flash at 5 Pa. At the same time, the deposition of the system of layers according to the invention proceeded as follows: argon was fed into a vacuum chamber at a pressure of 2.10 ¹ Pa while simultaneously titrating the titanium with an electron beam at a power of 2.5 KW for 2 minutes. In the next step, the argon feed was gradually stopped and then the acetylene was continuously added to a pressure of 7.10 " ² Pa while reducing the power of the evaporation source to 2.0 KW. The TiC _x layer formation process for these parameters took an additional 3 minutes. Described previously formed on a substrate of high-speed steel layer of TiC _{0, 95} having a thickness of 3.0 microns, which was diffusion bonded to the substrate through a thin layer of titanium.

Example 2

In another case, a method for preparing layers of TiC verified under otherwise identical conditions as in Example 1, but with the difference that in the vacuum chamber in the first step the impregnation of argon to a pressure 2.IQ ^"1 Pa and simultaneously vaporized titanium in the performance of the electron ' source of 2.5 KW for 1 minute, after which the argon pressure was adjusted to 5. IO ” ² Pa. After reaching this pressure was continuously infused into the chamber acetylene, up to a pressure of 3.10 Pa sňčasnébO ^_1 'evaporation of titanium in the performance of the electron source of 2.0 kW for 5 minutes. After completion of the process, the total thickness of the thus prepared layer was 4.1 .mu.m.

According to the method of the present invention, on a high-speed steel support, a layer system comprising a titanium backing layer and a Tic _x layer with a continuous depth concentration profile was formed, where x varied from surface to surface in the range of 0.9 to 0.2.

Claims (1)

SUBJECT A method of preparing a wear resistant titanium carbide thin film on an electrically conductive solid substrate that forms a cathode in an ion cladding system with an electron beam source vapor deposition process, characterized in that the solid electrically conductive substrate heated to a temperature greater than 300 ° C is treated with vapor plasma. titanium and an inert gas, usually argon, under reduced pressure Invention, the pressure in the range of 10 ⁴ to 10 Pa, to thereby subsequently treated under reduced pressure in the range 10 ^'2 and 10 Pa plasma formed by vapor of titanium and a hydrocarbon, usually acetylene or para titanium and mixtures of hydrocarbon and inert' gas, the concentration The hydrocarbon continuously increases in the ratio to the titanium range from 0.2 to 0.7 and thereafter in the range from 0.7 to 1.0.