Process for making corrosion-resistant amorphous-metal coatings from gas-atomized amorphous-metal powders having relatively high critical cooling rates through particle-size optimization (PSO) and variations thereof

Abstract

A system for the deposition of full-density, pore-free, corrosion-resistant, thermal-spray amorphous-metal coatings for the protection of a less corrosion resistant substrate. The system comprises using particle-size optimization (PSO) to ensure that the amorphous metal particles are small enough to ensure that the critical cooling rate is achieved throughout the amorphous metal particles.

1 . A method for deposition of amorphous-metal coatings, comprising the steps of: 
 using particle-size optimization to produce an amorphous-metal coating from amorphous metal particles, said particle-size optimization ensuring that said amorphous metal particles are small enough that the critical cooling rate is achieved throughout the amorphous metal particles, and    using said amorphous metal powders for thermal-spray deposition of the amorphous-metal.    
   
   
       2 . The method for deposition of amorphous-metal coating of  claim 1  wherein said particle-size optimization uses small enough amorphous metal powders in a mixed feed to ensure that the critical cooling rate is achieved throughout the amorphous metal particles.  
   
   
       3 . The method for deposition of amorphous-metal coating of  claim 1  wherein said critical cooling rate is higher than ≧100 K per second.  
   
   
       4 . The method for deposition of amorphous-metal coating of  claim 1  wherein said critical cooling rate is a lower than ≦100 K per second.  
   
   
       5 . The method for deposition of amorphous-metal coating of  claim 1  including predictive computational codes used for the prediction of the optimum particle size for producing thermal spray coatings from amorphous metals without devitrification.  
   
   
       6 . The method for deposition of amorphous-metal coating of  claim 1  including using codes based upon the simultaneous solution of differential equations that: (1) quantify the devitrification kinetics within amorphous metal particles of various sizes, based upon kinetic measurements from wedge casting, differential scanning calorimetry, and differential thermal analysis; (2) quantify the temperature history within amorphous particles of various sizes, based upon transient heat transfer calculations within the spray gun, sub-sonic or hypersonic spray, and at the surface being sprayed; (3) quantify softening within the sprayed particles, and account for the deformation and flow of particles at the surface being sprayed.  
   
   
       7 . The method for deposition of amorphous-metal coating of  claim 1  including extension of a predictive computational design tool for particle-size optimization described in item (2) to metal-ceramic composites involving amorphous metal particles, other metal, glass and ceramic particles where phase transformations can occur.  
   
   
       8 . The method for deposition of amorphous-metal coating of  claim 1  including any full-density, pore-free, corrosion-resistant, thermal-spray or cold-spray amorphous-metal protective coating where post-spray high-density infrared fusing to achieve lower porosity and higher density than otherwise possible, thereby enhancing corrosion resistance and damage tolerance of the metal-ceramic composite coating.  
   
   
       9 . The method for deposition of amorphous-metal coating of  claim 1  including any full-density, pore-free, corrosion-resistant, thermal-spray or cold-spray amorphous-metal protective coating where post-spray high-density infrared fusing to achieve lower porosity and higher density to achieve enhanced metallurgical bonding, and to control damage tolerance through controlled devitrification of the amorphous metal matrix.  
   
   
       10 . The method for deposition of amorphous-metal coating of  claim 1  including using predictive computational codes used for the prediction of the optimum light flux for producing thermal spray coatings from amorphous metals without devitrification, or with controlled levels of devitrification for achieving desired mechanical properties.  
   
   
       11 . The method for deposition of amorphous-metal coating of  claim 1  including using codes based upon the simultaneous solution of equations that: (1) quantify the reflection, scattering and absorption of the incident light flux, as a function of source wavelength, polarization and intensity, and as a function of amorphous-metal coating composition, microstructure, and surface roughness; (2) quantify the devitrification kinetics within deposited amorphous metal particles, based upon kinetic measurements from wedge casting, differential scanning calorimetry, and differential thermal analysis; (3) quantify the temperature history within the amorphous-metal coating, based upon transient heat transfer calculations within the coating and substrate; and (4) quantify softening, melting and flow of the deposited amorphous metal.  
   
   
       12 . The method for deposition of amorphous-metal coating of  claim 1  including any full-density, pore-free, corrosion-resistant, thermal-spray or cold-spray amorphous-metal protective coating where post-spray high-density infrared fusing to achieve lower porosity and higher density to achieve enhanced metallurgical bonding, and to control damage tolerance through controlled devitrification of the amorphous metal matrix and including extension of the predictive computational design tool for said high-density infrared fusing to metal-ceramic composites involving amorphous metal particles, other metal, glass and ceramic particles where phase transformations can occur.  
   
   
       13 . The method for deposition of amorphous-metal coating of  claim 1  including any full-density, pore-free, corrosion-resistant, thermal-spray or cold-spray amorphous-metal protective coating where post-spray high-density infrared fusing to achieve lower porosity and higher density to achieve enhanced metallurgical bonding, and to control damage tolerance through controlled devitrification of the amorphous metal matrix and including extension of the predictive computational design tool for said high-density infrared fusing to metal-ceramic composites involving amorphous metal particles, other metal, glass and ceramic particles where phase transformations can occur, wherein said ceramics include compatible metal oxides, carbides, nitrides and/or other materials.  
   
   
       14 . The method for deposition of amorphous-metal coating of  claim 1  including enabling amorphous metal atomization processes, where the yield of optimally sized particles is substantially enhanced with feedback control.  
   
   
       15 . The method for deposition of amorphous-metal coating of  claim 1  including enabling amorphous metal atomization processes, where the yield of optimally sized particles is substantially enhanced with feedback control, wherein said process uses real-time measurements of atomized particle size distribution, measured with optical single particle analyzers, or multi-color laser Doppler velocimetry, to precisely control operating parameters that include, but not limited to: temperature of the molten metal and coolant gas, differential nozzle pressure, and mass flow rates.  
   
   
       16 . The method for deposition of amorphous-metal coating of  claim 1  including enabling particle-size classification processes for separation of optimally sized amorphous metal particles from a broader particle size distribution.  
   
   
       17 . The method for deposition of amorphous-metal coating of  claim 1  including enabling particle-size classification processes for separation of optimally sized amorphous metal particles from a broader particle size distribution, wherein said processes separate amorphous-metal particles based upon their differences in aerodynamic drag, which are size dependent.  
   
   
       18 . A method for deposition of an amorphous-metal coating on a surface, comprising the steps of: 
 using particle-size optimization to produce amorphous-metal amorphous metal particles, said particle-size optimization ensuring that said amorphous metal particles are small enough that the critical cooling rate is achieved throughout the amorphous metal particles, and    using a thermal-spray deposition process for directing said amorphous metal powders to the surface to provide the amorphous-metal coating.    
   
   
       19 . The method for deposition of amorphous-metal coating of  claim 18  including enabling particle-size classification processes for separation of optimally sized amorphous metal particles from a broader particle size distribution, wherein said processes separate amorphous-metal particles based upon their differences in aerodynamic drag, which are size dependent, wherein differential motion can be induced in amorphous metal particles that are suspended in an inert gas atmosphere by first imparting an electrostatic charge to the particles, and then subjecting them to an electrostatic force.  
   
   
       20 . The method for deposition of amorphous-metal coating of  claim 18  including enabling particle-size classification processes for separation of optimally sized amorphous metal particles from a broader particle size distribution, wherein said processes separate amorphous-metal particles based upon their differences in aerodynamic drag, which are size dependent, wherein differential motion can be induced in amorphous metal particles that are suspended in an inert gas atmosphere by first imparting an electrostatic charge to the particles, and then subjecting them to an electrostatic force, and wherein capture of desired particle sizes can be triggered with optical sensors based upon optical single particle analyzers or multi-color laser Doppler velocimetry.  
   
   
       21 . The method for deposition of amorphous-metal coating of  claim 18  including enabling particle-size classification processes for separation of optimally sized amorphous metal particles from a broader particle size distribution.  
   
   
       22 . The method for deposition of amorphous-metal coating of  claim 18  including enabling particle-size classification processes for separation of optimally sized amorphous metal particles from a broader particle size distribution, wherein said processes will separate amorphous-metal particles based upon the size-dependent differences aerodynamic drag in a cyclonic flow field.  
   
   
       23 . The method for deposition of amorphous-metal coating of  claim 18  including enabling particle-size classification processes for separation of optimally sized amorphous metal particles from a broader particle size distribution, wherein said processes will separate amorphous-metal particles based upon the size-dependent differences aerodynamic drag in a cyclonic flow field. Differential motion can be induced in amorphous metal particles by entraining them in a cyclonic separator, and wherein said capture of desired particle sizes can be triggered with optical sensors based upon either optical single particle analyzers or multi-color laser Doppler velocimetry.  
   
   
       24 . The method for deposition of amorphous-metal coating of  claim 18  including induction-heated spray process for producing full-density, pore-free, corrosion-resistant, thermal-spray amorphous-metal coatings for the protection of a less corrosion resistant substrate.  
   
   
       25 . The method for deposition of amorphous-metal coating of  claim 18  including induction-heated spray process for producing full-density, pore-free, corrosion-resistant, thermal-spray amorphous-metal coatings for the protection of a less corrosion resistant substrate, wherein said process, ambient-temperature particles entrained in an ambient-temperature flowing gas, and then passed coaxially through an induction coil, where the oscillating electric field (frequency of 1 to 100 kHz) couples directly to the amorphous metal particles, without direct heating of the carrier gas.  
   
   
       26 . The method for deposition of amorphous-metal coating of  claim 18  including induction-heated spray process for producing full-density, pore-free, corrosion-resistant, thermal-spray amorphous-metal coatings for the protection of a less corrosion resistant substrate, wherein said process, ambient-temperature particles entrained in an ambient-temperature flowing gas, and then passed coaxially through an induction coil, where the oscillating electric field (frequency of 1 to 100 kHz) couples directly to the amorphous metal particles, without direct heating of the carrier gas, and wherein said particle-specific heating allows more rapid cooling of the amorphous metal particles than possible in processes where the gas is used to heat the particles.  
   
   
       27 . The method for deposition of amorphous-metal coating of  claim 18  including induction-heated spray process for producing full-density, pore-free, corrosion-resistant, thermal-spray amorphous-metal coatings for the protection of a less corrosion resistant substrate, wherein said process, ambient-temperature particles entrained in an ambient-temperature flowing gas, and then passed coaxially through an induction coil, where the oscillating electric field (frequency of 1 to 100 kHz) couples directly to the amorphous metal particles, without direct heating of the carrier gas, and wherein said particle-specific heating allows more rapid cooling of the amorphous metal particles than possible in processes where the gas is used to heat the particles, and wherein said processing can be applied to ceramic particles, provided that a higher frequency is used (1 to 10 GHz).  
   
   
       28 . The method for deposition of amorphous-metal coating of  claim 18  including tools and devices enabled specifically by the aforementioned metal-ceramic composite materials and coatings, which have exceptional corrosion resistance, wear resistance, and damage tolerance.  
   
   
       29 . The method for deposition of amorphous-metal coating of  claim 18  including tools and devices enabled specifically by the aforementioned metal-ceramic composite materials and coatings, which have exceptional corrosion resistance, wear resistance, and damage tolerance, wherein said devices and tools may include, but are not limited to: containers for the shipment, long-term storage, and disposal of spent nuclear fuel (SNF) and high-level radioactive waste (HLW); ground support systems for underground tunnels; pressure vessels, piping and heat exchangers for the chemical process industry, fossil power plants, and nuclear power plants; pump shafts and impellers; valve seats; propellers, rudders, shafts and bearings for marine applications; non-sparking trays and racks for munitions; gun barrels; projectiles; armor; rail guns; etc.