SEDIMENTATION OF ULTRADISPERSED DIAMONDS IN CITRATE COPPER PLATING ELECTROLYTE

Abstract

The processes of aggregation and sedimentation of ultradispersed diamonds (UDD) in citrate copper plating electrolyte used for obtaining composite electrochemical coatings was investigated. The study of sedimentation and aggregation resistance was carried out for the purpose of selecting the concentration of UDD in citrate copper plating electrolyte. It was necessary to obtain composite copper plating featuring advanced operational properties (increased hardness, wear resistance, corrosion resistance), as well as to attain new properties (antifriction, catalytic). UDD content in electrolyte varied from 0,2 to 2,0 g/l. UDD particle size distribution in electrolyte was determined using the Malvern Mastersizer 2000 laser diffraction analyzer both as soon as suspension had been prepared and after 10-day holding. Aggregation and sedimentation resistance of UDD suspension in citrate copper plating electrolyte was investigated gravimetrically with a continuously weighed quartz cup immersed into the above mentioned suspension. The quartz cup was connected to the Sartorius R200D analytical balance by quartz fiber. The above experiment resulted in obtaining the relationship between the mass of UDD debris and the time Q = f(t).The obtained relationship was used to determine the relative particle size distribution. Sedimentation resistance has been proved to be greatly affected by the process of particle aggregation intensified by means of diamond concentration strengthening. Appropriate aggregation and sedimentation resistance results were derived from UDD suspension in citrate copper plating electrolyte at a concentration of 1,0 g/l. In this case the combination of high disperse phase content and aggregation and sedimentation resistance produced copper composite coatings with enhanced operational properties.