The most effective way is to add alloying elements in the matrix

The foreign visiting delegation of green laser pointerhas arrived. Usually re-cladding layer of laser technology are hoping to get the following results: high bonding strength, which called for the interface coating and the substrate have a good metallurgical bond; remelted layer formation, fewer defects, which called for the full Bear remelted layer fusion, oxygen, become uniform dense; coating the substrate is not diluted or diluted only slightly, to keep the coating material or the specific requirements of high strength to avoid a mixture of substrate and coating. Laser cladding layer cracking, crack one of the important reasons is between cladding alloy and substrate differences in coefficient of linear expansion, so the choice of coating material must first consider the expansion coefficient of the coating and the substrate on the line match, considering the coating and substrate thermal expansion coefficient differences between the bonding strength of the coating, thermal shock resistance, in particular, anti-cracking performance. Currently, most studies are based on laser cladding layer and the substrate linear expansion coefficient matching principle cladding material selection and component design. The traditional view is that, in order to prevent cracking and peeling off the coating, the coating and substrate should satisfy the linear expansion coefficient of the identity of the principle that both should be as close as possible, taking into account the characteristics of laser cladding process, the substrate and coating floor heating and cooling processes are not synchronized, the linear expansion coefficient of the cladding layer in a certain range of the smaller, more cladding layer is not sensitive to cracking. The foreign visiting delegation of green laser pointer is visiting the workshop of green laser pointer.
In the laser cladding technique, the need for coating materials is another important concern is the melting point of thermal physical properties. Cladding alloy and the substrate material difference between the melting point is too large, can not form a good metallurgical bonding. In addition to considering the thermophysical properties of cladding materials, we must also consider the rapid heating of the laser under mobility, chemical stability, hardening phase particles and the new node, the wettability of the metal phase and high temperature phase transition when the fast-cooling characteristics. Cladding process, the wetting is also an important factor. In particular, to obtain satisfactory metal-ceramic coatings, and ceramics must deposit sign of the Zodiac has a good wettability. To improve wetting, mainly based on the following principles. Appropriate choice of laser cladding process parameters, such as increasing the cladding temperature, cladding to reduce the surface energy of liquid metal. Change the chemical composition of the matrix. The most effective way is to add alloying elements in the matrix, as in the system by adding Ti Cu/Al2O3 improve wettability and white, add the activity in the matrix elements of Hf, also help to improve between the matrix and particle wettability. The surface of ceramic particles to improve the status and structure, that is clad with ceramic particle surface treatment to improve its surface energy. Common treatment methods include mechanical, physical and chemical cleaning, electrochemical polishing and coating, etc. As in the A1 matrix composites, the ceramic surface with the formation of Ag colloidal infiltration in the melt and the composition of Ag coating, the Ag and Al have a good wettability to form between the Al and the ceramic and the combination of good wetting. The foreign delegation of green laser pointer takes part in the opening meeting of 200mw laser pointer.
Laser cladding materials are mainly used in thermal spray and thermal spray-like material class materials, which include self-fluxing alloy, carbide dispersion or composite materials, ceramic materials, these materials have excellent wear resistance, corrosion resistance and usually in the form of powder used, cladding used flame spray. Self-fluxing alloy material according to the matrix can be divided into nickel-based alloys, cobalt based alloys and iron-based alloys. Its main characteristic is contain silicon and boron, so self-deoxy-performance and self-slag, which is called self-flux. Principle of self-fluxing alloys when the alloy is remelted, silicon and boron were formed Si02 and B202,, and in the cladding layer formed on the surface film. This film on the one hand to prevent oxidation of the alloy elements, on the other but also with the formation of oxides of these elements diboride acid slag, resulting in relatively low oxide content, porosity less cladding layer.