A Surface Modification Method for Changing the Surface Wettability of Impregnated Graphite

A technology of impregnating graphite and surface infiltration, which is applied in the field of surface modification of solid materials, can solve the problems of complex steps, inability to change infiltration properties, and high difficulty in coating realization, and achieves the effect of simple and easy method.

Active Publication Date: 2019-01-29
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in the existing methods, coating and other technologies are difficult to implement and the steps are complicated. The method of changing the surface morphology can only change the degree of wetting, but cannot change the nature of wetting (hydrophilic / hydrophobic).

Method used

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  • A Surface Modification Method for Changing the Surface Wettability of Impregnated Graphite
  • A Surface Modification Method for Changing the Surface Wettability of Impregnated Graphite
  • A Surface Modification Method for Changing the Surface Wettability of Impregnated Graphite

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] Before laser modification, the surface contact angle measured by surface tensiometer was 75.6°, as figure 1 shown in . Set the laser scanning speed to 2000mm / s, the laser repetition frequency to 20kHz, the laser power to 12.5W, and the number of scans to 1. After the local area is irradiated, the surface contact angle measured by the surface tensiometer becomes 17.2°, as figure 2 Shown at left.

Embodiment 2

[0032] The surface contact angle measured by surface tensiometer before laser modification was 75.6°. Set the laser scanning speed to 2000mm / s, the laser repetition frequency to 20kHz, the laser power to 10W, and the number of scans to 1. After irradiating the local area, the surface contact angle measured by the surface tensiometer becomes 47.3°, as figure 2 shown on the right.

Embodiment 3

[0034] The surface contact angle measured by surface tensiometer before laser modification was 75.6°. Set the laser scanning speed to 2000mm / s, the laser repetition rate to 20kHz, the laser power to 7.5W, and the number of scans to 1. After irradiating the local area, use the surface tensiometer to measure the surface contact angle to 96°, as image 3 Shown at left.

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Abstract

The invention provides a surface modification method for changing the surface infiltration performance of an impregnated graphite. The surface modification method comprises the steps that a relevant laser marking machine pattern is drawn according to the shape of the impregnated graphite, the surface modification range is determined, and laser marking is performed according to a pattern filling scheme; a test piece to be modified is clamped to a laser operation table, and laser beam focusing is completed; the laser marking parameters are set, wherein the Q frequency is 20 kHz and the jump speed is 2,000 mm / s; different scanning parameters are selected for machining according to difference influences of laser machining on the surface topography and surface features, and the surfaces with the different infiltration performance are obtained, wherein the contact angle ranges 6.7 degrees to 135.8 degrees; meanwhile the whole mechanical performance of a graphite material is not influenced; and the method is easy to implement and can be popularized easily on a large scale.

Description

technical field [0001] The invention belongs to the technical field of surface modification of solid materials, and in particular relates to a surface modification method for changing the surface wettability of impregnated graphite. Background technique [0002] Due to the high temperature stability, corrosion resistance, and radiation resistance of graphite materials, graphite materials are widely used in seals, bearings and other fields as a typical friction pair material. Graphite impregnated with phenolic resin has better mechanical properties, so it is often used in thrust bearings under heavy load conditions, and forms friction partners with other hard materials. [0003] In mechanical seals and thrust bearings, the friction and wear characteristics between friction pairs determine the service life and maintenance cycle of key components of these mechanical systems to a certain extent. The wettability of the material greatly affects the friction and wear characteristi...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B41M5/00
CPCB41M5/00
Inventor 刘莹宋智翔郭飞刘向锋王玉明
Owner TSINGHUA UNIV
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