Abstract The new method starts with the coating metal in particle form, mixed with the particles to be coated. The mixture is heated, e.g., in a gas-fired furnace tube or by means of a plasma torch to a temperature sufficient to bring at least some of the metal to a molten and/or vapour state. The fluid metal is thus formed within the total particle mixture and transfers or condenses onto the particles to be coated. Depending on the proportion of metal in the starting mixture and the temperature to which the mixture is heated, the substrate particles become all-over coated or spotcoated with metal. The method can be performed continuously by continuously feeding the particles through a heating zone, and a high rate of processing is possible in apparatus of small size. The principal substrate particles in view are particles of glass, vitrocrystalline material, ceramics or plastics.
A METHOD OF DISCONTINUOUSLY APPLYING A COATING METAL TO THE SURFACES OF SUBSTRATE PARTICLES OF ANOTHER MATERIAL WITH THE USE OF A HEATED ZONE AND A ZONE THAT IS COOLER RELATIVE TO THE TEMPERATURE OF SAID HEATED ZONE, COMPRISING THE STEPS OF: A. FORMING A MIXTURE OF PARTICLES OF SAID COATING METAL AND SAID SUBSTRATE PARTICLES WHEREIN A MAJOR PORTION BY WEIGHT OF SAID MIXTURE IS CONSTITUTED BY SAID SUBSTRATE PARTICLES, B. PASSING SAID MIXTURE INTO A STREAM OF HOT GAS TO FORM SAID MIXTURE INTO A LOOSE CONDITION IN SAID HEATED ZONE AND TO EFFECT HEATING OF SAID PARTICLES OF SAID MIXTURE AND TO MELT AT LEAST SOME OF SAID COATING METAL PARTICLES SO THAT SAID MELTED METAL PARTICLES WILL FORM SPOTS OF METAL COATING AT A MULTIPLICITY OF SPACED PLACES DISTRIBUTED OVER THE ENTIRE SURFACE OF THE PARTICLE, C. CAUSING SAID SPOT-COATED PARTICLES TO PASS WHIL MAINTAINED IN LOOSE CONDITION BY SAID HOT GAS STREAM, FROM SAID HEATED ZONE TO SAID COOLER ZONE, WHEREIN SAID COATING SPOTS SOLIDIFY, AND D. SUBSEQUENTLY COLLECTING SAID SPOT-COVERED SUBSTRATED PARTICLES.
Claim 2
Independent Claim
178 words
A METHOD OF DISCONTINUOUSLY APPLYING A COATING METAL TO THE SURFACES OF SUBSTRATE PARTICLES OF ANOTHER MATERIAL WITH THE USE OF A HEATED ZONE AND A ZONE THAT IS COOLER RELATIVE TO THE TEMPERATURE OF SAID HEATED ZONE, COMPRISING THE STEPS OF: A. FORMING A MIXTURE OF PARTICLES OF SAID COATING METAL AND SAID SUBSTRATE PARTICLES WHEREIN A MAJOR PORTION BY WEIGHT OF SAID MIXTURE IS CONSTITUTED BY SAID SUBSTRATE PARTICLES, B. PASSING SAID MIXTURE INTO A STREAM OF HOT GAS TO FORM SAID MIXTURE INTO A LOOSE CONDITION IN SAID HEATED ZONE AND TO EFFECT HEATING OF SAID PARTICLES OF SAID MIXTURE AND TO MELT AT LEAST SOME OF SAID COATING METAL PARTICLES SO THAT SAID MELTED METAL PARTICLES WILL FORM SPOTS OF METAL COATING AT A MULTIPLICITY OF SPACED PLACES DISTRIBUTED OVER THE ENTIRE SURFACE OF THE PARTICLE, C. CAUSING SAID SPOT-COATED PARTICLES TO PASS WHIL MAINTAINED IN LOOSE CONDITION BY SAID HOT GAS STREAM, FROM SAID HEATED ZONE TO SAID COOLER ZONE, WHEREIN SAID COATING SPOTS SOLIDIFY, AND D. SUBSEQUENTLY COLLECTING SAID SPOT-COVERED SUBSTRATED PARTICLES.
Claim 3
Dependent Claim
24 words
The method as claimed in claim 1, wherein said mixture contains not more than 10 percent by weight of said particles of coating metal.
Claim 4
Dependent Claim
35 words
A method according to claim 1, wherein said substrate particles are initially non-rounded particles and the said heating of the said mixture of particles causes said substrate particles to become rounded under surface tension effects.
Claim 5
Dependent Claim
60 words
A method according to claim 1, wherein said substrate particles are particles of light-transmitting material and the composition of the particles which are mixed and heated together with such substrate particles is such that the said coating formed on the individual substrate particles gives the coated particles better reflex-reflecting properties in respect of incident light rays than the uncoated particles.