Polycrystalline Diamond Compacts with Interstitial Material
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Polycrystalline diamond compact cutting elements used in earth-boring tools face thermal instability and mechanical brittleness due to catalyst material presence, leading to delamination and chemical breakdown at high temperatures, and fully leached diamond tables are more brittle and difficult to secure.
Innovation Solution
The development of polycrystalline compacts with a mixture of smaller and larger grains of hard material, interspersed and interbonded with an interstitial material such as borides, carbides, or non-catalytic metals, which are formed using a high temperature/high pressure process to create a thermally stable and mechanically durable cutting element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If catalyst material is present in the diamond table, then the diamond grains can be sintered together to form polycrystalline diamond compact, but the catalyst material causes thermal damage and chemical breakdown at high temperatures
Solution Approach 1:
The patent extracts and removes the catalyst material from the diamond table through chemical leaching processes. The catalyst material is dissolved using acids such as hydrochloric acid, nitric acid, or their mixtures, leaving the diamond grains bonded together without the harmful catalyst present in the final product.
Solution Approach 2:
The patent changes the chemical composition parameters of the diamond table by controlling the leaching process. By adjusting acid concentration, temperature, and exposure time, the catalyst material is selectively removed while preserving the diamond grain structure and inter-granular bonds.
2Reliability
If catalyst material is completely removed from the diamond table, then thermal stability is improved, but the diamond table becomes more brittle and difficult to secure to substrate
Solution Approach 1:
The patent applies partial leaching action by controlling the leaching process to remove a specific portion of the catalyst material rather than completely eliminating it. This partial removal achieves sufficient thermal stability improvement while retaining enough catalyst to maintain mechanical integrity and bonding capability.
Solution Approach 2:
The patent creates local quality variations in the diamond table by allowing different regions to retain different amounts of catalyst material. The leaching process can be controlled to create gradients or selective removal patterns that optimize both thermal stability and mechanical properties in different zones of the cutting element.
3Strength
If high temperature is applied during sintering to form polycrystalline diamond compact, then the diamond grains bond together effectively, but the catalyst material causes internal stress and delamination
Solution Approach 1:
The patent removes the catalyst material from the diamond table after sintering to eliminate the source of internal stress and delamination. By extracting the catalyst post-sintering, the strong inter-granular bonds formed during high-temperature processing are preserved while the harmful thermal expansion effects are eliminated.
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 solution provides improved thermal stability and mechanical durability of cutting elements, reducing brittleness and enhancing their performance at high temperatures without the need for complete catalyst removal, while maintaining effective bonding and ease of attachment to substrates.
Implementation Method 1
Polycrystalline diamond compact cutting elements are typically formed by sintering and bonding together relatively small diamond grains under conditions of high temperature and high pressure
Implementation Method 2
the cobalt (or other catalyst material) in the cutting element substrate may be swept into the diamond grains during sintering and serve as the catalyst material for forming the inter-granular diamond-to-diamond bonds
Implementation Method 3
This internal stress is at least partially due to differences in the rates of thermal expansion between the diamond table and the cutting element substrate to which it is bonded
Implementation Method 4
it is known to leach catalyst material from the cutting face, from the side of the diamond table, or both, to a desired depth within the diamond table
Data Source
AI summary
Polycrystalline compacts include smaller and larger hard grains that are interbonded to form a polycrystalline hard material. The larger grains may be at least about 150 times larger than the smaller grains. An interstitial material comprising one or more of a boride, a carbide, a nitride, a metal carbonate, a metal bicarbonate, and a non-catalytic metal may be disposed between the grains. The compacts may be used as cutting elements for earth-boring tools such as drill bits, and may be disposed on a substrate. A particulate mixture includes a first plurality of grains of hard material having a first average grain size of about five hundred nanometers (500 nm) or less and having a coating formed over the grains of hard material. The coating comprises at least one of a boride, a carbide, a nitride, a metal carbonate, a metal bicarbonate, and a non-catalytic metal.