A surface pretreatment process of diamond-like coating workpiece

Abstract

The invention relates to a surface pretreatment process for a diamond-like carbon coated workpiece. The process comprises nine steps of mixed dry sandblasting of white corundum and brown corundum, dry sandblasting of glass beads, ultrasonic acid solution washing, tap water rinsing, ultrasonic alkaline solution washing, tap water rinsing, primary ultrasonic deionized water rinsing, secondary ultrasonic deionized water rinsing and drying. The mixed dry sandblasting of white corundum and brown corundum is used for removing large-area deep stains on the surface of the workpiece, including iron rust, oil stains, glue and other attachments; the dry sandblasting of glass beads is used for removing white corundum and brown corundum particles embedded in the workpiece; the ultrasonic alkaline solution washing and the rinsing are used for removing small stains on the surface of the workpiece, and the workpiece is placed into a vacuum tank body for performing a diamond-like carbon vacuum coating process after drying. The process is the process before diamond-like carbon vacuum coating and is a prerequisite for ensuring that the surface of the coated metal workpiece has a relatively clean surface and obtains relatively high coating binding force.

Description

technical field [0001] The invention relates to the field of film coating, in particular to a surface pretreatment process for improving the bonding force between the coating and the substrate during the vacuum coating process of the diamond-like coating. Background technique [0002] The bonding force between the coating and the substrate is a common problem in the field of coating engineering, and it is also the most critical factor that determines whether a coating can be promoted. As a new type of functional coating, diamond-like carbon coating (DiamondLikeCarbon-DLC) mainly includes the following aspects for improving its bonding force: [0003] (1) Surface pretreatment [0004] The surface pretreatment of the workpiece before DLC coating is very important, which directly determines the final bonding strength of the coating and the substrate. Before the coating, if the surface of the workpiece is not cleaned thoroughly, that is, there are thick oxide scales or other s...

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Problems solved by technology

[0005] 1. The stain will turn into a plasma state under the action of the electric field, polluting the entire tank

This will cause the composition of the DLC coating to be impure and affect the performance parameters of the coating itself, such as hardness, friction coefficient, surface energy, etc.;

[0006] 2. The conductivity of stains and scale is relatively poor. When a negative bias is applied to the workpiece, because electrons cannot escape from the workpiece smoothly, they will accumulate on the stain or scale. Once the charge accumulates to a certain extent, it will Release in the form of arc, which will cause "arc spots" on the surface of the workpiece, and may even cause the workpiece to be scrapped;

[0007] 3. Ion beam cleaning is carried out when the stains and scales are not thoroughly cleaned during pretreatment. In most cases, it is difficult to remove large stains and thick scales, because the bonding force between stains, scales and the matrix is ​​usually Very poor, such coating adhesion is difficult to meet the requirements

[0009] During the DLC coating process, due to the difference in the thermal expansion coefficient and the coherent matching of the crystal structure between the coating material and the base material, it may cause the peeling of the DLC

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