Since April, China's A-share lab-grown diamond sector has experienced a sharp upward trend. According to Wind data, from April 1st to the close on June 5th, the Wind Cultured Diamond Concept Index (8841557.WI) surged by a cumulative 75.18%, with all related stocks in the sector rising. Many investors have been inquiring about the commercialization progress of related products through exchange interactive platforms. The market enthusiasm for the lab-grown diamond sector is driven by the opening of a new industrial track: diamond-based thermal interface materials, which are moving from the laboratory to AI server cooling modules. Companies like Jiangsu Boamax Technologies Group Co.,Ltd. (SHE: 002514), Sinomach Precision Industry Group Co.,Ltd. (SHE: 002046), and Henan Liliang Diamond Co.,Ltd. (SZSE: 301071) have made significant inroads into this new field, alongside several non-listed companies. However, industry insiders interviewed point out that the journey from prototype samples to finished products, and from small-batch production to large-scale mass production, for diamond heat dissipation materials remains long.
Listed Companies Rushing to Enter, Three Technical Paths Emerge
The high market interest in diamond-copper composite materials stems from the increasingly severe thermal challenges faced by AI computing power chips. Traditional cooling materials, primarily copper and aluminum, meet the thermal needs of most standard electronic devices. However, with the advancement of AI technology, high-performance computing, and the trend towards thinner, lighter devices, their limitations are becoming apparent. Nvidia's latest Vera Rubin architecture GPU has a Thermal Design Power (TDP) soaring to 2300W, with local chip heat flux density exceeding 1000W/cm². Under such extreme conditions, traditional copper-based cooling materials have hit a physical ceiling—copper's thermal conductivity is about 400W/(m·K), and its coefficient of thermal expansion differs significantly from silicon-based chips, making it prone to thermal stress during temperature cycles, leading to packaging layer fatigue and solder joint failure. Diamond's theoretical thermal conductivity is as high as 2200W/(m·K), five times that of copper and four times that of silver. Its thermal expansion coefficient closely matches semiconductor materials like silicon and GaN, and it combines high thermal conductivity with high electrical insulation, making it almost tailor-made for cooling high-power chips.
China is the world's largest producer of synthetic diamonds, accounting for over 95% of global output, with Henan province contributing over 80% of domestic capacity. However, in recent years, the lab-grown diamond industry has been mired in a price downturn. The demand for AI computing power cooling has opened a "second growth curve" for the diamond industry. Statistics show that, to date, several A-share companies have announced their entry into the semiconductor diamond-copper heat dissipation sector. These companies fall into two main categories: one comprises material manufacturers specializing in synthetic diamond production, such as Henan Huanghe Whirlwind Co.,Ltd. (SHA: 600172), Henan Liliang Diamond Co.,Ltd. (SZSE: 301071), and Huifeng Diamond, leveraging their CVD/MPCVD equipment and technical expertise to produce diamond for thermal applications. The other category includes industrial service providers excelling in precision machining and equipment manufacturing, such as Sinomach Precision Industry Group Co.,Ltd. (SHE: 002046) and Jiangsu Boamax Technologies Group Co.,Ltd. (SHE: 002514), extending into composite material packaging through capabilities in grinding, metal forming, and other processes.
Sinomach Precision Industry Group Co.,Ltd. (SHE: 002046) recently stated that three main technical paths/products have emerged in the diamond heat dissipation field: diamond-copper composite materials, CVD polycrystalline diamond heat sinks, and single-crystal diamond. Single-crystal diamond heat sinks have a thermal conductivity of about 2000W/(m·K) or higher; polycrystalline diamond heat sinks about 1500W/(m·K); and diamond-copper composites about 800W/(m·K). The market evaluates these primarily based on production cost, manufacturing process, and suitability for downstream applications.
Diamond-copper composite materials are currently the fastest solution to reach industrial application. An industry insider noted that these composites are made by combining diamond particles with a copper matrix using processes like powder metallurgy, liquid infiltration, or spark plasma sintering. Since diamond is extremely hard (Mohs hardness 10), precision machining is very difficult. Furthermore, copper and diamond are inherently non-wetting with weak interfacial bonding, making the technical barrier to combining them even higher. By compositing 30% to 50% by volume of diamond particles into the copper matrix, thermal conductivity can reach 600-800W/(m·K), 1.5 to 2 times that of pure copper (401W/(m·K)), while also maintaining metal workability and cost control. This makes it the most commercially viable high-thermal-conductivity composite material currently available.
Public information indicates that companies like Jiangsu Boamax Technologies Group Co.,Ltd. (SHE: 002514), Sinomach Precision Industry Group Co.,Ltd. (SHE: 002046), and Huifeng Diamond have deeply invested in diamond-copper composites. On December 25, 2025, Jiangsu Boamax Technologies Group Co.,Ltd. (SHE: 002514) established Slac Thermal Control Technology (Changzhou) Co., Ltd., focusing specifically on thermal control technologies for computing infrastructure, including the design, development, and production of high-thermal-conductivity composites and core thermal management components. On March 31 this year, the company signed a "Technology Development Contract" with the University of Science and Technology Beijing to commission research on the "Development of a New Generation High Thermal Conductivity Metal/Diamond Composite Material Preparation Device." On May 17, the company announced via its official WeChat account the successful development of heat sink structural components using diamond composite materials. The company employs a gas pressure infiltration method and ultra-hard mold material processing technology to create practical, high-thermal-conductivity structural heat sink plates from diamond-copper. Currently, related products are undergoing testing and validation with key customers.
Sinomach Precision Industry Group Co.,Ltd. (SHE: 002046) utilizes technologies like powder metallurgy, liquid infiltration, and spark plasma sintering (SPS). It has now formed a product matrix covering single-crystal diamond, polycrystalline diamond, and diamond-copper composite materials. Diamond-copper composite materials have been sent to customers for sampling and validation. Products across all technical routes for civilian heat dissipation applications are currently in the downstream customer validation stage.
Mass Commercialization Yet to Materialize
Although the thermal conductivity of diamond-copper composites may not be as impressive on paper as graphene, they enable true three-dimensional heat dissipation and have a thermal expansion coefficient that perfectly matches chips. They are considered by the industry as the "ultimate cooling solution" for the AI computing era, but this depends on solving cost and mass production issues. Looking at the commercialization progress of various companies, most are still in the "small-batch supply" or "customer validation" stages, with a significant gap remaining before achieving mass production and stable revenue contribution. Sinomach Precision Industry Group Co.,Ltd.'s (SHE: 002046) products are currently mainly supplied to the defense industry. Sifangda has entered small-batch supply but awaits subsequent large-volume orders from customers. Henan Huanghe Whirlwind Co.,Ltd.'s (SHA: 600172) 8-inch production line has just commenced operation, requiring time for capacity ramp-up.
On the application side, media reports indicate that in April 2026, diamond-copper composite material developed by the Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, completed cluster deployment at the Zhengzhou National Supercomputing Internet core node, marking its first large-scale commercial use in China. The material, applied as a thermal interface pad in close contact with the chip, works in conjunction with an immersion-phase-change liquid cooling system. Actual measurements showed an 80% improvement in chip module heat transfer capability, a 5°C reduction in core temperature, and a 10% increase in chip performance release. Compared to top international computing clusters of the same period, overall energy savings exceeded 30%.
Industry observers point out that in the above commercial case, the diamond-copper composite material functioned as a "thermal interface pad" (interface thermal material) working alongside a liquid cooling system, rather than as an independent cooling solution. It is widely believed within the industry that the large-scale commercial adoption of diamond-copper composites in data centers still faces three bottlenecks: technology, cost, and industry chain coordination.
Technologically, the core challenge lies in the inherent non-wetting nature of diamond and copper, making interfacial thermal resistance control a key technical hurdle. If the interfacial transition layer does not meet expectations, thermal conductivity can be significantly reduced, even falling below that of pure copper. Additionally, performance uniformity in large-sized products and the difficulty of precision machining due to diamond's high hardness are practical issues hindering industrialization.
Cost-wise, while diamond-copper composite material costs only one-fifth to one-tenth that of pure diamond, when combined with processing costs, it remains prohibitive for many medium- to low-power scenarios. Pure diamond heat sinks are even more expensive. Currently, domestic intelligent computing centers adopting batch solutions use diamond-copper composites, which cost one-fifth to one-tenth of pure diamond.
At the industry chain level, a coordinated system from material supply to chip design, packaging/testing, and system integration is not yet mature, lacking unified reliability evaluation standards and suffering from lengthy validation cycles. Semiconductor-grade thermal materials require rigorous reliability certifications, such as 1000-hour high-temperature, high-humidity testing, with certification cycles often exceeding six months.
On May 26, Henan Liliang Diamond Co.,Ltd. (SZSE: 301071) issued a risk warning announcement, explicitly stating that the application scenarios for "diamond heat dissipation materials" have not yet reached a stage of large-scale marketization, have not impacted the company's main business or revenue, and that recent significant stock price fluctuations indicate high speculative risks. On June 3, Huifeng Diamond issued an announcement noting its stock price had risen sharply in the short term, significantly deviating from market trends, indicating overheated market sentiment. However, the company's fundamentals have not undergone major changes, and there is no undisclosed material information.
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