Influence of plating solution pH on the structure of electroless Co-Ni-P alloy coating

In particular, the phosphorus content, which in turn affects the structure and properties of the coating 1 Experimental conditions and methods of chemistry. The matrix containing gold chain layer is the red copper film key liquid bundle of 20151. The mating time is jade, and the average thickness of the plating layer is 4 to measure the deposition rate of the plating by the weighing method. Electroless plating was analyzed on a 3E3 electron probe. 1 pick up the chemical composition of the gold layer. The microstructure of the coating was analyzed on a rotating anode, X-ray diffractometer and transmission electron microscope. The results were observed and observed. 2.1 Plating solution 1! The value of the electroless plating, alloy plating deposition speed of the value of the mention. In electroless plating, the deposition rate of the alloy layer is gradually increased. When the value 1 is 10, with the increase of the Qiu value, the deposition rate is 74. When the plating is carried out, the first is the catalytic dehydrogenation reaction of the reducing agent hypophosphite, and then the electrons are transferred to the substrate surface, and the metal ions are obtained by electron reduction deposition on the catalyst. Surface 1 is known from the formula 3, the higher the value of the bath, the faster the reduction reaction of +, if the bath is acidic, the chemical equilibrium moves to the left, the reduction rate of the metal ions is greatly reduced, and even the plating cannot be formed. Under alkaline conditions, cobalt-antimony alloy can form forged layer gas, but the aging of the forging solution reduces the severity of the reduction. 2.2 Bath solution! The effect of the value on the composition of the electroless plating 0,1 alloy coating, addition, nickel content and phosphorus content reduction From the previous, the most of the gold-forming ions in the plating solution prepared from the base formula of this test is 0, and the value is increased. High, favorable, reduction, cobalt content of the coating, reduced value addition, cobalt content naturally reduced because the electrode potential of the media is higher than cobalt, and the reducing ability is stronger than that of cobalt. Therefore, under the condition that the price is low, add, so when! When the value is reduced, the nickel content of the coating is increased to some extent.

It is well known that during chemical deposition, it is not purely a transient intermediate product formed from the catalytic process of the reducing agent. The value of 1 can be increased, the value of the plating solution is increased, the difficulty of phosphorus decomposition by metaphosphoric acid, and the participation of co-deposited phosphorus in the bath. cut back. The phosphorus content of the coating also decreases.

In addition, the electron probe energy spectrum analysis showed that the phosphorus content in the grain boundary and the grain boundary under the condition of different values ​​and values ​​at the initial stage of the plating formation, the transmission coefficient of the alloy chain layer and the electric diffraction pattern 1 plating bath 1 value and chemical monuments; 1 composite plating deposition rate and chemical composition of the lower value, the diffraction grating for the two diffuse, emission diffraction ring, peripheral halo ring vaguely. Is typical. Crystal structure zero 23; 1 value rise, the diffraction ring becomes clear and narrow, amorphous features are less obvious than the above, for the microcrystalline structure 2; when 1 value continues to rise, the diffraction ring is narrower, the boundary is clear, The degree of diffuse scattering weakened, showing a tendency to crystallize, with fine grains 2. When the median value rose to 10, there was no diffuse scattering, the diffraction ring peeled off, and there were clear diffraction spots, respectively, of 100 and 101 respectively. The crystal surface is diffracted, crystallized, and the grain size is large. The ray diffraction results also reflect the same change. This shows that when the output value of the plating solution 1 changes, the plating structure of the electroless plating 1 alloy is diversified. Non-product micro-products + crystalline state transition occurred in the stratum structure = the materialistic point of view that the chemical composition of the material influences its microstructure, and ultimately determines its performance. It is clear that the change in bath energy is caused by the formation of an amorphous state. It is known that (3) transition elements and the like and the metalloid element 8 are increased, and the probability and stability of the amorphous formation are also increased. Therefore, the electroless plating and the chemical composition of the alloy 4 have basic conditions for forming an amorphous state.

Electroless plating. In the initial stage of the formation of the alloy plating layer, the reduced cobalt atoms formed a crystal core violently on the catalytic surface. The 1 cliff, Hui, the female, and the Qing basin were segregated on the product boundary to reduce the product boundary energy. The driving force for grain growth is reduced. Inhibition of grain growth is known from 1 and 1. In a given range, the lower the value of the plating solution, the higher the phosphorus content in the coating, and the phosphorus element in the grain boundary. more. The stronger this work, the finer the product. Microstructures were gradually formed and microcrystals were obtained. When the 3 phosphorous contained cerium, the amorphous structure was formed. When the 13 value was increased, the phosphorus content difference between the intragranular and grain boundaries decreased. The retarding effect of growth is weakened, and the factors favoring the formation of amorphous state are reduced. The reduced alloy plating layer can continue the growth of the original crystal orientation and become a crystalline state.

At the same time, the co-deposition of phosphorus will also change the crystal orientation of the original cobalt, forming a vertical step along the direction and the plane, and then converting it into an amorphous structure gas. In practice, it is intuitively reflected in the lower Under the condition of deposition speed, an amorphous plating layer is easily formed. In fact, under the premise of normal deposition, the lower deposition rate corresponds to the lower, higher and higher phosphorus content. Therefore, the approximate structure of the forged layer can be judged according to the deposition rate during plating. This is similar to the fact that Watanabe's research on electroplating is similar to the theory of electroless plating. It is more about the characterization and the rate of precipitation of a layer than that of amorphous layer and phosphate. The liquid and value changes are now macroscopically divided by the plating rate and the deposition rate. The addition of the alloy plating to the structure and properties changes the value, but also to the stability of the entire process conditions and electroless plating, 4 alloy coating deposition rate of phosphorus content structure and The relationship between the performances was studied. Under the condition that the amount of stabilizer added in the plating bath is relatively high and the operating temperature is lower, the long-term rejection of the phosphorous and the plating solution are similar to each other. Non-product layer. It seems that, compared with the Bei Xue plating, 1 gold plating is more sensitive to changes in the plating bath's 1 value due to its structure and properties. 3 Conclusions The higher the value of the bath, the faster the deuterium reductive deposition rate is. The immersion property of the forging solution is reduced due to the difference in metal ion reduction ability. With the decrease of the 1 value, the cobalt content in the electroless plating 4 alloy plating layer is reduced, and the nickel content and the phosphorus content are added to the plating bath 1 value and the deposition speed is influenced by Chemical plating, the chemical composition of the alloy coating is mainly, the lower the value of the content and thus affect the structure and performance of the coating, the slower the deposition rate, the higher the phosphorus content, the easier to get the amorphous coating.

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2 Shen Ning. Surface treatment process manual. Shanghai Shanghai Science and Technology Press, 199255.

3 Guo Yicheng, Wang Zhenxi. Amorphous Physics, Beijing Science Press, 1984, 84 4 Huang Zixun, Wu Shansu. Plating theory. Beijing China Agricultural Machinery Press, 1982, 76.

5 Watanabe, amorphous plating method and application. Beijing Beihang University Press, 1992, 15.