Method for improving contact fatigue life of spray coating layer

A technology of contact fatigue and spray coating, which is applied in the direction of coating, metal material coating process, fusion spraying, etc., can solve the problems of affecting the contact fatigue life of the coating, the service performance of the spray coating is limited, and the bonding strength is not high, so as to eliminate Adverse effects, increased hardness, good deposition effect

Active Publication Date: 2012-09-05
ACADEMY OF ARMORED FORCES ENG PLA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the limitations of the thermal spraying process, the pores, microcracks and other defects of the sprayed coating limit its service performance under the condition of cumulative fatigue damage.
In the prior art, the bonding method of the plasma sprayed iron-based self-fluxing alloy coating and the substrate is only a mechanical fit formed by the impact of the velocity of the molten particles on the rough surface after sandblasting. The bonding strength is not high, and there are a large number of cracks on the interface, such as Image 6 shown
Due to the low bonding strength and the existence of interface cracks, the coating is prone to failure due to the peeling off of the entire layer in the early stage of service under the action of large contact stress, which greatly affects the contact fatigue life of the coating.

Method used

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  • Method for improving contact fatigue life of spray coating layer
  • Method for improving contact fatigue life of spray coating layer
  • Method for improving contact fatigue life of spray coating layer

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0025] In this specific embodiment, the plasma sprayed iron-based self-fluxing alloy coating is used as the experimental coating. Embodiment 1 Application method of the present invention prepares iron-based self-fluxing alloy coating

[0026] Concrete preparation steps:

[0027] 1. Optimization of the spraying parameters of the working coating: use orthogonal experiments to calculate the spraying parameters of the working coating.

[0028] In the embodiment, the three parameters that have the greatest impact on coating performance in plasma spraying, i.e. spraying distance, spraying voltage, and spraying current are extracted, and are determined according to the power and average thermal efficiency of the HEPjet supersonic plasma spraying equipment and the melting point of the sprayed material The parameter levels of , as shown in Table 1 of the orthogonal experiment, fixed the main air flow rate, powder feeding rate and coating thickness factors. In plasma spraying, these t...

Embodiment 2

[0062] Embodiment 2 Evaluation of the contact fatigue performance of the coating prepared in Example 1 of the present invention and the coating prepared in the prior art

[0063] In order to investigate the contact fatigue performance of the coating (prepared in Example 1) prepared by the new process method proposed here, the coating prepared by the new process method and the coating directly prepared (without preparing the bonding bottom layer and using orthogonal calculation optimization, the spraying parameters are shown in Table 5)

[0064] table 5

[0065]

[0066] Under the same experimental conditions (stress level and friction conditions), 10 groups of contact fatigue experiments were carried out. The experimental method: spray the coating on the prefabricated substrate, and use the contact fatigue testing machine to conduct the contact fatigue experiment. The experimental equipment is: YS-1 ball-on-disk contact fatigue testing machine independently developed by Ya...

Embodiment 3

[0067] Depend on Figure 7 It can be seen that under the same number of cycles, the failure probability of the coating prepared by the new process method is significantly lower than that of the original process, and the L of the coating prepared by the new process method 10 (minimum life), L 50 (nominal life) and L a (Characteristic life) is greater than that of a coating without a bonded primer. And the slope of the Weibull curve of the coating prepared by the new process is relatively large, which indicates that the dispersion of the fatigue data of the coating is small, and the contact fatigue life of the coating is easy to evaluate. It can be seen that the new process of the present invention significantly improves the contact fatigue performance of the sprayed coating. Embodiment 3 Evaluation of contact fatigue performance of the coating prepared in Example 1 of the present invention and the coating prepared in the prior art

[0068] The coating prepared by Example 1 ...

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Abstract

The invention discloses a method for improving the contact fatigue life of a spraying coating layer, which is characterized by comprising the following steps of: (1) optimizing spraying parameters of a work coating layer, namely calculating the spraying parameters of the work coating layer by using an orthogonal experiment; (2) preparing a Ni / Al bonding bottom layer; and (3) spraying the work coating layer by using a plasma spraying technique. The method adopts an orthogonal design namely a modern applied mathematics method to optimize the spraying parameters, and obtains an optimal parametercombination according to different properties of coating materials. The method is applied to the optimization of thermal spraying parameters of various coating layer materials. The invention providesa new process method through which a coating layer with high hardness, low porosity, good comprehensive performance and high bonding strength is obtained by optimizing a working layer and preparing an undercoat. Through experimental comparison, the new process method can significantly improve the contact fatigue life of the coating layer.

Description

technical field [0001] The invention relates to a method for improving the fatigue life of a coating, in particular to a method for improving the contact fatigue life of a sprayed coating by combining an orthogonal experiment with a primer coating. Background technique [0002] With the progress of society, many equipment parts are used in high-temperature, high-speed, high-corrosion environments, which accelerates the scrapping of parts due to surface failure. If the surface failure occurs and the parts are replaced, the processing cost will be greatly increased and the residual value of the waste parts will be wasted. Preparing remanufactured coatings on the surface of waste parts is an effective means to solve such problems. Preparing hard coatings on the surface of waste parts by thermal spraying and other technologies can not only maximize the use of waste parts, but also use rational design of coatings Remanufactured parts are used in harsher working conditions. Ther...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C23C4/04C23C4/12G06F17/50C23C4/134
Inventor 徐滨士王海斗朴钟宇濮春欢王国普
Owner ACADEMY OF ARMORED FORCES ENG PLA
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