Cemented Carbide Substrate Corrosion Resistance via Metal Additives
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Solution Overview
Problem
The existing cemented carbide substrates in Polycrystalline Diamond Compacts (PDCs) suffer from poor corrosion resistance, leading to reduced usability and service life due to galvanic corrosion and erosion, especially in drilling applications where complex chemical environments are encountered.
Innovation Solution
A cemented carbide substrate with a binding phase comprising cobalt and specific metal additives such as nickel, chromium, manganese, molybdenum, tin, copper, palladium, silver, aluminum, and platinum, which improves corrosion resistance by altering the corrosion mechanism, is used in conjunction with a tungsten carbide, and a preparation method involving sintering at high temperatures and pressures to form a polycrystalline diamond compact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a cobalt-base cemented carbide is used as the substrate, then the impact toughness is improved, but the corrosion resistance deteriorates due to galvanic corrosion between the binder and carbide
Solution Approach 1:
The patent changes the chemical composition parameters of the binding phase by adding specific metal elements (nickel, chromium, manganese, molybdenum, tin, copper, palladium, silver, aluminum, or platinum) to the cobalt-based binder. This modifies the electrochemical properties and corrosion behavior of the binding phase, reducing galvanic corrosion while maintaining cobalt's toughness-contributing properties.
Solution Approach 2:
The patent creates a composite binding phase system combining cobalt with one or more metal additives. This composite approach leverages cobalt's ductility and toughness while the added metals provide enhanced corrosion resistance, creating a synergistic effect that resolves the contradiction between toughness and corrosion resistance.
2Duration of action of stationary object
If the binding phase composition is optimized for corrosion resistance, then the service life is improved, but the manufacturing complexity increases due to multiple element ratios
Solution Approach 1:
The patent applies local quality by selectively adding specific metal elements to the binding phase at controlled ratios. Rather than uniformly complicating the entire material system, the invention locally modifies the binding phase composition to achieve corrosion resistance, leaving the rest of the PDC structure relatively simple and manufacturable.
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 improved corrosion and erosion resistance of the cemented carbide substrate extends the service life of PDCs by enhancing their ability to withstand harsh drilling environments, maintaining mechanical properties and reducing wear and tear.
Implementation Method 1
For WC—Co cemented carbide, galvanic corrosion is easily formed between the binder and carbide, promoting the dissolution of the binder and damaging the integrity of the microstructure.
Implementation Method 2
sintering the assembly block to obtain the polycrystalline diamond compact
Data Source
AI summary
Embodiments relate to the field of superhard materials, and to a polycrystalline diamond compact (PDC) and a preparation method therefor, and a cemented carbide substrate. The cemented carbide substrate includes a binding phase and a tungsten carbide. The binding phase includes a cobalt and a metal additive. The metal additive is selected from one or more of nickel, chromium, manganese, molybdenum, tin, copper, palladium, silver, aluminum, and platinum. By introducing specific elements and controlling proportions of the elements, the corrosion-resistant binding phase is formed, thereby improving the corrosion resistance of the cemented carbide substrate. Due to that the corrosion-resistant binding phase changes the corrosion mechanism of the cemented carbide substrate, the changed corrosion mechanism is more adapted to the usage scenarios of the PDC, effectively improving the corrosion resistance and erosion resistance of the PDC, and thereby improving the service life of the PDC.