Introduction

The importance of Silicon Carbide (SiC) ceramic material to the world today can’t be overemphasized. It’s one of the most talked-about advanced ceramic materials because of its usefulness and impressive mechanical properties. Nearly every engineering firm and high-tech industry you see today uses SiC materials in one way or the other. Thanks to recent technology, manufacturers have discovered that sintering silicon carbide can help you get cost-effective, high-grade SiC.

In today’s article, you will learn about the properties and applications of the pressureless sintered silicon carbide type. You will also discover the differences between reaction sintering and pressureless sintering of Silicon Carbide. Lastly, you will see the current international market trends and market value of sintered silicon carbide.

Characteristics of Sintered Silicon Carbide

Sintered silicon carbide is made industrially by sintering pure SiC powders and heating them under temperatures reaching 2,100°C. After proper heating and machining, the SiC powders fuse to form a dense, hard ceramic material. Non-oxide sintering aids like Boron are very essential in this process of improving silicon carbide hardness. Moving forward, SSiC materials are available in two major grades: reaction sintered silicon carbide and pressureless sintered silicon carbide.

These Sintered Silicon Carbide (SSiC) materials are gaining popularity because they are like an improved version of silicon carbide. The reason for this is that SSiC materials usually have superior mechanical properties and durability. This is because they’ve been exposed to further industrial processes involving extreme temperatures and heating. They also have a higher density, purity performance level, and strong resistance to corrosion, chemicals, wear, and tear.

Properties of Sintered Silicon Carbide

Some outstanding properties of sintered silicon carbide are:

• Low coefficient of thermal expansion

• High compressive strength and hardness.

• Low porosity

• High percentage of pure SiC.

• High melting point

• Stability even under high temperatures.

• Strong resistance to corrosion, wear, and tear.

• Excellent thermal conductivity and thermal shock resistance.

• Durable refractory materials

Applications of Sintered Silicon Carbide

As a result of the exciting properties of sintered silicon carbide, you can use it in a variety of applications, including:

• Production of ceramic heat sinks.

• Manufacturing ceramic bearings.

• Military vehicles and bulletproof vests

• Production of kiln linings

• Manufacturing turbine components

• Production of excellent silicon carbide semiconductors.

• Production of balls, seats, and liners for valves.

Comparison between pressureless Sintering and reaction sintering of silicon carbide

Sintered silicon carbide can be manufactured industrially in two distinct sintering patterns. These patterns are: reaction sintering of silicon carbide and the pressureless sintering of silicon carbide. Let’s take a close look at both of them briefly.

Reaction Sintering of Silicon Carbide

This method is very straightforward if used to sinter SiC. Here, you can use very low temperatures of about 1,650°C to heat a mixture of carbon and SiC powders. Ensure that the mixture is porous enough to allow liquid silicon to infiltrate the pores. Now, this is where the reaction takes place as you sinter (heat). You will notice that the liquid silicon you just poured reacts with the carbon, and excess sintered dense SiC is produced.

It’s a high-energy-consuming process, but like you’ve just read, the process is very fast and simple too. It is more suited to the large-scale production of sintered SiC materials. Those are some of the major advantages it has over pressureless sintering of silicon carbide. However, most of the materials produced from reaction sintering are usually not dense enough to withstand very high temperatures. You cannot rely so much on them because their porous nature makes them crack easily under mechanical stress.

Products from reaction-sintered silicon carbide can still serve various unique purposes and applications in the aerospace and engineering industry.

Pressureless Sintering of Silicon Carbide

This method of sintering silicon carbide doesn’t involve adding external pressure to the high-purity SiC powders at your disposal. A vacuum furnace with high temperatures between the ranges of 2,100°C and 2,200°C can be used to achieve this pressureless sintering. All that’s needed is to heat the silicon carbide powder in the vacuum till the powder fuses to form a very dense polycrystalline ceramic plate. The fusing process passes through the solid state diffusion phase, and particles thereby form necks.

The pressureless sintering of silicon carbide helps you manufacture high-quality quality cost-effective sintered silicon carbide. It offers you several unique advantages over the reaction sintering of silicon carbide. Some of these advantages include:

• Reducing the cost of production since you do not necessarily need external pressure to sinter the silicon carbide powder.

• Pressureless sintering of silicon carbide can help you produce any kind of complex-shaped ceramic material of your choice.

• Using the pressureless sintering of silicon carbide method helps you avoid the limitations of molds during the machining process.

• Pressureless sintering of silicon carbide can help you produce superior SSiC materials with high temperature resistance and flexural strength.

Reaction sintering saves you time and reduces your cost of production, while pressureless sintering gives you pure, superior quality SSiC. So you can consider these factors and make your choice based on your product specifications and the outcomes you expect.

Properties of Pressureless Sintered Silicon Carbide

It has been shown how easy it is to manufacture this pressureless grade of sintered silicon carbide in the industry. Now, some of the amazing properties of these pressureless sintered SiC materials are:

• Has a density ranging between 3.1 -3.2g/cm³.

• High Vickers hardness rating of 2500 HV0.5.

• 99% pure silicon carbide

• Chemically inert material.

• Low coefficient of thermal expansion.

• Has a porosity of less than 0.2% due to its high density it has.

• It can withstand temperatures of up to 1,600°C.

• Compressive strength of 3,000 MPa and Flexural strength of 600 MPa.

• Highly elastic, possessing a Young’s modulus of about 410 GPa.

• Good thermal conductor, with a thermal conductivity reaching 120 W/mK.

Applications of Pressureless Sintered Silicon Carbide Materials

The applications of pressureless sintered SiC materials cut across a wide range of industrial sectors. The metallurgical industry, electronics, engineering firms, aerospace, automotive, and many other manufacturing industries all benefit from these pressureless sintered SiC. Here are some of the valuable applications that pressureless sintered silicon carbide can help you with:

• Production of mechanical rings, nozzles, and gaskets for heavy industrial machines.

• High temperature applications like industrial kilns, ceramic feedthroughs for electrical isolation, and heat sinks in semiconductors.

• Production of optical mirrors that utilize short wavelengths for efficiency.

• Manufacturing of abrasives, mechanical seals, cutting tools, grinding tools, and furnace linings in high-tech industries.

• Production of military armors, ballistic missile components, and bulletproof vests.

• Production of mechanical pumps, high electronics devices, and semiconductors due to silicon carbide’s hardness and high thermal conductivity.

• Pressureless sintered SiC can help you produce scratch-resistant hard coatings for other materials.

Current Market Value and Market Trends of Sintered Silicon Carbide

As of 2023, the international market value of sintered silicon carbide was a whopping $725 million. Since then, global demand has tremendously increased, and so has the value. In 2024, it rose to about $1.8 billion, impressive, right? With a Compound Annual Growth Rate (CAGR) of 7.6%, the market still has the potential to expand much further.

Some key players in this industry are top firms like CoorsTek, USA, and Saint-Gobain Performance Ceramics and Refractories, France.

If you are looking to purchase high-quality and durable sintered SiC materials, GGSCeramics is your best bet. We have a wide range of affordable, high-performance reaction-sintered SiC and pressureless sintered SiC materials to satisfy you.

Frequently Asked Questions

What is the energy content of sintered silicon carbide?

The energy content of sintered silicon carbide is around 200.

Is Direct Sintered SiC better than Reaction Bonded SiC?

Yes, you can say direct sintered SiC grade is better than reaction bonded SiC grade because it performs better under extremely high temperatures.

Why is sintered silicon carbide the best material for producing seals?

The exceptional hardness and abrasiveness of sintered silicon carbide help you to produce high-strength seals. These seals are reliable, long-lasting, and resistant to wear and tear due to the sintered silicon carbide material.

Conclusion

Sintered silicon carbide’s impressive properties are gradually making the world easier and more enjoyable to live in. Yes, it’s safe to say so, considering its many applications and valuable contributions to many sectors and economies globally. You can call SSiC materials the future of advanced ceramics. Now is the best time for you to invest!