What Are The Factors That Affect The Thermal Conductivity Of AlN Ceramic Substrates?

First of all, let’s overview AlN Ceramics
AlN is a covalently bonded compound with a stable structure and hexagonal wurtzite structure without the existence of other allotypes. Its crystal structure is the AlN4 tetrahedron produced by the disproportionation of aluminum atoms and adjacent nitrogen atoms as the structural unit; the space group is P63mc, which belongs to the hexagonal crystal system.

The main features of aluminum nitride ceramics:
(1) High thermal conductivity, which is 5-10 times that of alumina ceramics;
(2) The thermal expansion coefficient (4.3×10-6/℃) matches the semiconductor silicon material (3.5-4.0×10-6/℃);
(3) Good mechanical properties;
(4) Excellent electrical properties, with extremely high insulation resistance and low dielectric loss;
(5) Multi-layer wiring can be performed to achieve high density and miniaturization of packaging; (6) Non-toxic, good Conducive to environmental protection.

Various factors affecting the thermal conductivity of AlN ceramics
At 300K, the theoretical thermal conductivity of AlN single crystal material is as high as 319W/(m K), but in the actual production process, due to the purity of the material, internal defects (dislocations, pores, impurities, lattice distortion), grain The thermal conductivity is also affected by various factors such as orientation and sintering process, which are often lower than the theoretical value.

In summary:
Selecting the appropriate sintering aids in the composite system can achieve a lower sintering temperature of AlN and effectively purify the grain boundaries, and obtain AlN with higher thermal conductivity.

What Are The Factors That Affect The Thermal Conductivity Of AlNCeramic Substrates

AlN Schematic diagram of the crystal structure

BN Nozzle for Metal Gas Atomisation

Boron Nitride is oxidation and corrosion-resistant, making it suitable for high-temperature processes such as steel processing and ceramic manufacturing.
Key features:
1. Inert – oxidation resistant up to 850ºC in air, 2000ºC inert atmospheres
2. Resistant to corrosion by most molten metals
3. Non-toxic

BN Nozzle for Metal Gas Atomisation

It is a ceramic with a high melting point; it is tough enough to prevent cracks; it has high thermal shock resistance, and it’s easily machinable. In addition, molten metals cannot ‘wet’ the surface of boron nitride, which means that it is not easily clogged during the atomization process.

Under high vacuum, boron nitride can survive up to 1800 °C. A gas atmosphere can push this even further to 2100 °C. This means that boron nitride will remain solid through the melting of most metals.

Boron nitride has a very low thermal expansion. Together with the high heat conductivity, this ensures that the material has very high shock resistance. It can easily withstand the rapid gradations in temperature inside the atomizer. It does not break or crack under thermal stresses.

It is also highly machinable, allowing us to make small threads, holes, and other finer details with high precision and tolerance. Nozzles made from boron nitride can be easily customized, allowing confined as well as free geometries.

The Three Most Commonly Used Ceramic Materials For Pcbs

Due to the properties of ceramics, ceramic PCBs can be placed in high-pressure or high-temperature environments, traditional PCB substrate materials may exhibit flaws in extreme conditions. In the article, we will discuss three common ceramic PCBs.

Metallized Ceramic PCB

The three most commonly used ceramic materials for PCB manufacturing are:

Alumina (Al2O3) – The mechanical strength, chemical stability, thermal conductivity, and electrical properties of Al2O3 is advantageous compared to other oxide ceramics. The abundance of a raw material makes alumina the most commonly used ceramic substrate material. Al2O3 ceramic PCBs are used in automobile sensor circuits, shock absorbers, and engines. The high thermal stability of Al2O3 ceramic PCBs improves the performance and thermal efficiency of the circuits used in automobiles.

Aluminum Nitride (AlN) – The high thermal conductivity and coefficient of expansion are two properties that make AlN noteworthy as a substrate material in the PCB industry. The thermal conductivity of AlN varies in the range of 170 W/mK to 220W/mK. The CTE of AlN ceramic matches with silicon semiconductor chips, which establishes a good bonding between the two, thus making their assembly reliable. AIN is used in sensor circuits in automobiles, as it can withstand extreme temperatures, corrosion, and vibration while providing efficient, accurate, and sensitive sensor signals.

Beryllium Oxide (BeO) – BeO is a ceramic PCB substrate material with a thermal conductivity around nine times that of Al2O3 and greater than metal aluminum. BeO showcases better chemical stability than AlN and high electrical isolation comparable with Al2O3e. BeO is used in applications where the PCB is subjected to high temperatures or in high-density PCBs facing space limitations to provide air or liquid cooling.

Innovacera 10th Anniversary Celebration

Xiamen, August 5, 2022-Today marks the 10th anniversary of the establishment of Innovacera, a global manufacturer in technical ceramic industry.

In its first decade as a standalone company, Innovacera has strengthened its position in the advanced ceramic industry, expanded its footprint, and offered ever-more innovative and responsible technical ceramic solutions.

Reflecting on 10 years of progress, James Qiu, General Manager of Innovacera said, “I take great pride in what we have accomplished over the last decade, and I want to thank all those who have accompanied us on our journey thus far – our employees, our longstanding customers, and our partners.

The Celebration includes with a planned 10 Year Anniversary activity at the Huayi Hotel. This event bring together Innovacera’s team with its partners, and friends in a business networking atmosphere with special presentations about Innovacera’s history as well as its clients greeting. At the same time, Innovacera sales office’s employees also prepared some put on performance. Below is some photos for reference:

Innovacera looks forward to many more anniversary celebrations in the future as its footprint continues to grow as a reliable supplier in innovative and creative technical ceramic solutions for marketing and technology with clients.

What is ceramic injection molding (CIM)?

Ceramic injection molding (CIM) refers to the process by which custom ceramic parts are fabricated using the injection mold process similar to that used with plastics. A pelletized blend of Alumina powder and certain binders are pre-heated and then forced under high pressure into a custom-made mold to form parts to the customer’s specific part design. Once the part is removed from the mold, it undergoes several additional processes including sintering at high temperature.

What is ceramic injection molding (CIM)

Materials used in the ceramic injection molding

When it comes to specific materials in ceramic injection molding, there’s a catalog of available options on the market. These materials have different properties, especially in reference to their hardness, density, temperature stability, etc. The most reliable materials used for ceramic injection molding include:

* Alumina ceramics: This is one of the most widely used materials in ceramic injection molding. Features include high levels of electrical insulation, resistance to corrosion and heat, and mechanical strength.

* Zirconia ceramics: As perhaps the strongest ceramic material, Zirconia is used for a variety of applications, including medical and dental purposes. Owing to its properties, Zirconia is highly resistant to wear and cracking, boasting an exceptional level of damage tolerance. It is also extremely stable in high-pressure situations.

* Aluminum Nitride: ALN combines high thermal conductivity with strong electrical resistance, making AlN an excellent solution for many electronic applications.

It’s important to note that there are other variations of Alumina and Zirconia ceramics that can be used. For instance, one material available is Alumina Toughened Zirconia that features high wear resistance and exceptional hardness.

Applications
The applications of CIM process are virtually boundless. As ceramic possesses high flexural strength, hardness and chemical inertness, it yields products that are highly corrosion resistant, wear resistant and have a long lifespan. Ceramic products are used in electronic assembly, tools, optical, dental, telecommunications, instrumentation, chemical plants and textile industries.