Analysis of the surface chemical composition of friction and wear

The composition and distribution of chemical elements in friction surface can be analyzed by energy spectrum analysis and X ray microanalysis.

The basic principle of energy spectrum analysis is that the surface is excited by the surface of the specimen with X ray, vacuum ultraviolet light beam or electron beam to produce optoelectronic and Auger electrons. Then the energy of these electrons can be measured and analyzed, and the chemical composition of the surface can be determined.

The basic principle of X ray microanalysis is that the elements and contents of the elements are determined by the effect of the electron beam on the surface of the specimen and the radiographic spectra of the elements. The elements are determined by the wavelength and intensity of different characteristics of the X rays.

Analysis of friction and wear surface structure

The surface structure changes of metal surface during friction and wear are usually analyzed by diffraction technique. Electron diffraction and X ray diffraction are commonly used.

The penetration ability of electron diffraction is small, and the scattering thickness is only 10-7 ~.

10-8 cm. Electron diffraction (XRD) can be used to analyze the friction surface of thin layers, such as adhesion and wear of metals and migration of friction pairs.

The X ray penetration ability is large, and the scattering layer thickness can reach 10-4 to 10-2 cm. X ray diffractometer is commonly used to analyze the structure of the thick friction surface. For example, this method is often used to study the change of crystal size after friction and wear of engine piston ring and cylinder liner, the transition from alpha iron to gamma after abrasive wear and the lubrication mechanism of lubricating oil additive on the surface of metal.

When the friction and wear test machine is tested, the change of the surface structure is the key to the study of the law and mechanism of friction and wear. The modern surface testing technology has been used to study the various phenomena of the friction surface. Heng Xu Xiaobian first let us know the first analysis method -- the analysis of the surface topography of friction and wear.

The changes of surface topography in friction process can be analyzed by surface profiler and electron microscope.

The surface profilometer moves evenly on the surface by measuring the touch needle, detecting and amplifying the stylus with the vertical motion of the surface profile, and depicting the contour curve of the surface. After the operation of the microprocessor, the change of the surface topography parameters can be directly measured.

At present, the commonly used surface microtopography analysis equipment is scanning electron microscope. The image of the electronic scanning is clear and three-dimensional, and the magnification range is wide (20-20000 times), and the detection range is also large.