Platinum Group Metal Catalysts for PIM Impurity Control
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Solution Overview
Problem
Powder injection molding (PIM) processes face challenges in maintaining purity due to affinity of powders with process gases, leading to undesirable impurities like oxides, nitrides, and hydrides, and the presence of carbon-based impurities from binder residues, which are difficult to control and result in substandard sintered alloy components.
Innovation Solution
Incorporating a platinum group metal, such as palladium, into the feedstock composition to catalytically remove carbon and oxygen impurities during the PIM process, ensuring the formation of sintered bodies with reduced impurity levels by using dual asymmetric centrifugal forces for coating and thermally induced catalytic removal processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional PIM process is used without platinum group metal, then manufacturing cost is lower, but carbon and oxygen impurity content in sintered bodies exceeds ASTM standards
Solution Approach 1:
Platinum group metal particles are introduced as intermediary catalysts in the feedstock composition. These catalysts facilitate the decomposition of organic binder and removal of carbon and oxygen impurities during sintering, enabling impurity control without requiring complex external processing equipment or multiple processing steps.
Solution Approach 2:
The chemical composition parameter of the feedstock is modified by adding platinum group metal at concentrations of 0.01-50 wt%. This compositional change enables catalytic activity that fundamentally alters the debinding and sintering mechanisms, allowing impurity removal through catalytic pathways rather than relying solely on thermal decomposition and atmospheric control.
2Ease of manufacture
If thermal debinding process is used to remove binder, then binder removal is achieved, but carbon-based impurities from binder residues remain in sintered bodies
Solution Approach 1:
The organic binder, which normally produces harmful carbon impurities when thermally decomposed, is converted into a beneficial source of carbon for catalyst formation. The binder decomposition provides carbon that reacts with oxygen to form CO/CO2 gases, while the platinum group metal catalysts facilitate this reaction and prevent carbon incorporation into the sintered metal matrix.
Solution Approach 2:
Platinum group metal particles act as intermediary catalysts during the thermal debinding process. They facilitate the decomposition of organic binder molecules and promote the formation of gaseous CO and CO2 products, preventing carbon residue formation. The catalysts enable the binder removal process to proceed cleanly without leaving carbon-based impurities in the final sintered body.
3Productivity
If powder has high affinity for process gases, then sintering process can proceed at standard conditions, but oxide, nitride and hydride impurities form in the sintered body
Solution Approach 1:
Platinum group metal particles serve as intermediary catalysts that modify the reaction pathways between reactive metal powders and process gases (O2, N2, H2). The catalysts facilitate controlled reactions that prevent unwanted oxide, nitride, and hydride formation while allowing the sintering process to proceed under standard atmospheric conditions without requiring complex vacuum or inert gas systems.
4Manufacturing precision
If ASTM standard purity levels are achieved through conventional methods, then extensive process control and atmosphere management are required, but this increases process complexity and cost
Solution Approach 1:
Platinum group metal catalysts are incorporated into the feedstock composition to internally manage impurity formation during sintering. This eliminates the need for complex external process control systems, vacuum equipment, or sophisticated atmosphere management. The catalysts perform the purification function within the material itself, achieving ASTM standard purity levels through a simple one-step sintering process under standard atmospheric conditions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method effectively controls carbon and oxygen content in sintered bodies to ASTM standard levels, improving the purity and properties of titanium alloys and cermets, enhancing their corrosion resistance and mechanical properties.
Implementation Method 1
at least a proportion of the carbon and/or oxygen is catalytically removed by the at least one platinum group metal
Implementation Method 2
the presence of a platinum group metal in a feedstock composition can result in the manufacture of finished sintered bodies having lower impurity concentrations
Implementation Method 3
thermally induced catalytic removal processes
Data Source
AI summary
The present invention relates to a method for controlling the carbon and/or oxygen content in a material byforming a feedstock composition comprising at least one powder, at least one platinum group metal and at least one binder; andforming the material by powder injection molding;wherein at least a proportion of the carbon and/or oxygen is catalytically removed by the at least one platinum group metal.