GALVANIC COATINGS OF IRON-COBALT COMPOUNDS WITH CERAMIC PARTICLES

Abstract: The invention concerns a galvanic treatment of metal surfaces with layers, composed mainly of iron and/or cobalt, during the galvanic process iron and cobalt compounds are deposited. The coating is during the process also filled with hard ceramic particles. By a thermal treatment at about 350 degrees Celsius the coating develops a high resistance against wear, partly due to the hard ceramic particles. The coatings produced this way distinguish themselves by an extreme longwearing and low coefficient of friction especially with dry friction. Use of the coatings on sliding surfaces of cylinders and pistons of internal combustion engines and compressors augment the mechanical efficiency and the longevity increases considerably. Also the consumption of lubricants for engines decreases.

Description: Galvanic coatings of iron-cobalt compounds with ceramic particles . The invention concerns a galvanic treatment of metal surfaces where layers, composed mainly of iron and/or cobalt, during the galvanic process iron and cobalt compounds are deposited. The coating is during the process also filled with hard ceramic particles. By a thermal treatment at about 350 degrees Celcius the coating develops a high resistance against wear, partly due to the hard ceramic particles. The this way produced coatings distinguish themselves by an extreme longwearing and low coefficient of friction especially with dry friction. Use of the coatings on sliding surfaces of cylinders and pistons of internal combustion engines and compressors augment the mechanical efficiency and the longevity increases considerable. Also the consumption of lubricants decreases. It is known from the American publication US-A-4.886.583 to deposit coatings of a nickel-cobalt matrix which is filled with ceramic particles. These coatings need a thermal treatment at temperatures between 550 and 620 degrees Celcius. Treatments like these can easily result in unacceptable distortions of the parts to be treated. The invention concerns galvanic depositrn . of a coating of cobalt and/or iron. In the bath are phosphorus and/or boron compounds and ceramic particles in suspension. With the deposit of the metal compounds of cobalt-phosphorus and/or iron-phosphorus and/or cobalt-boron and/or cobalt- phosphorus develope which are uniformly distributed in the metal matrix. The ceramic particles are embedded in the coating during the process . By a thermal treatment of some hours a hardening of the coating occurs . The process works as follows: -2- The to be coated parts are cleaned and placed in the bath. The bath is composed of a aqueous solution of : cobalt and/or iron ions of 0,1 Mol/L to saruration, preferably 0,65 Mol/L, phosphorus compounds of 0,05 Mol/L to saturation, preferable 0,3 Mol/L and/or boron compounds of 0,05 Mol/L to saturation, preferably 0,3 Mol/L Ceramic particles with a hardness of more then 900 H v according to Vickers the current is more than 5 Ampere per dm 2 the themperature of the bath is kept between 40 and 100 degrees Celcius, preferably circa 90 degrees Celcius. A thermal treatment of some hours at a temperature of 280 to 400 degrees Celcius. The result is a coating with a concentration of phosphorus and/or boron compounds of 1 to 20 percent by weight; the amount ceramic particles of 0,2 to 98 percent by weight, preferable 15 percent by weight. Discovered is that an addition of other metals is of no great influence of the quality of the coating when the amount is less than 50 percent and non-metals to 16 percent of the original bath preparation. With the same bath components it is possible to deposite the desired coating electroless where a reductor delivers the energy. The in this way obtained coatings turn out to be very resistant to wear under extreme circomstances to dry friction. Whem used in engines with internal combustion and compressors the lifespan is longer, the mechanical efficiency is augmented. The consumption of oil -tnrt f'τπt-wi11 be reduced.

Claims: -3- Claims . 1. Galvanic coatings composed of iron and/or cobalt with phosphorus and/or boron compounds which are filled with ceramic particles characterised by that the coatings contain as well as iron or cobalt, iron-phosphorus and/or iron-boron and/or cobalt-phosphorus and/or cobalt-boron compounds, whereby the coatings are filled with hard ceramic particles. 2. Galvanic coatings as in claim 1 characterised by that the galvanic bath has a concentration of 0,1 Mol/litre to saturation, preferably 0,65 Mol/litre as well as a concentration of 0,05 Mol/litre to saturation, preferably 0,3 Mol/litre, of phosphorus and/or boron compounds whereby the fine ceramic particles are present in suspension. 3. Galvanic coatings as in claim 1 and 2 characterised by that the galvanic bath permits additions of other metals onto fifty percent of the concentration of iron, cobalt, phosphorus and boron compounds. 4. Galvanic coatings as in claim 1, 2 and 3 characterised by that the ceramic particles have a minimum hardness of 900 H v according to Vickers. 5. Galvanic coatings as in claim 1, 2, 3 and 4 characterised by that the temperature of the bath is kept between 40 and 100 degrees Celcius. 6. Galvanic coatings as in claim 1, 2, 3, 4 and 5 characterised by that the current density is kept above 5 Ampere per Dm 2 . 7. Galvanic coatings as in claim 1, 2, 3, 4, 5 and 6 characterised by that the to be coated parts after the galvanic receive a thermal treatment of several hours at a temperature between 280 and 400 degrees Celcius. -4- 8. Galvanic coatings as in claim 1 , 2 , 3 , 4 , 5 , 6 and 7 characterised by that the coatings are deposited on sliding surfaces of cylinders and/or pistons of engines with internal combustion and compressors . * * * * *

Inventors: VAN DER SLUIS GUUS JOCHEM, VAN DER SLUIS, GUUS, JOCHEM
Applicants: SLUIS GUUS JOCHEM V D, VAN DER SLUIS, GUUS, JOCHEM
Application year: 1999
Main classification: C25D15
IPC codes: C25D5, C25D15