Alumina Composite Ceramic Sintering at Reduced Temperatures
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Solution Overview
Problem
Alumina-based materials lack sufficient mechanical strength and thermal conductivity for advanced electronic components, and alternative materials like aluminum nitride are costly due to high manufacturing temperatures and oxidation issues.
Innovation Solution
An alumina composite ceramic composition is developed, incorporating zirconia or yttria-stabilized zirconia, graphene oxide, and carbon nanotubes, which are mixed and sintered at reduced temperatures in a controlled atmosphere to enhance mechanical strength and thermal conductivity while maintaining electrical insulation properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If alumina is sintered at high temperature (1600°C or more) to achieve sufficient density and mechanical strength, then mechanical strength is improved, but manufacturing cost and energy consumption increase
Solution Approach 1:
The patent changes the sintering temperature parameter from conventional 1600°C or higher down to 1500°C or lower by introducing a sintering aid composition containing specific oxide combinations (such as Y2O3-Al2O3, Nb2O5-Al2O3, or Ta2O5-Al2O3 systems). This parameter change enables sufficient densification and mechanical strength at reduced temperatures, directly resolving the contradiction between mechanical strength improvement and energy consumption reduction.
Solution Approach 2:
The patent introduces a sintering aid composition as an intermediary substance that facilitates sintering at lower temperatures. The sintering aid acts as a mediator between the alumina particles, enabling bond formation and densification at 1500°C or lower where pure alumina would not sinter effectively. This intermediary enables the reduction of sintering temperature while maintaining mechanical strength.
2Temperature
If aluminum nitride is used as an alternative material to achieve high thermal conductivity and electrical insulation, then thermal conductivity is improved, but manufacturing cost increases due to high sintering temperature (1700°C or more) and reducing atmosphere requirements
Solution Approach 1:
The patent creates a composite material system combining alumina with specific sintering aids (Y2O3-Al2O3, Nb2O5-Al2O3, or Ta2O5-Al2O3 compositions) to achieve properties comparable to or exceeding pure aluminum nitride. This composite approach enables high thermal conductivity and electrical insulation at lower manufacturing costs by avoiding the expensive reducing atmosphere sintering process required for aluminum nitride.
Solution Approach 2:
The patent replaces expensive aluminum nitride material with a more cost-effective alumina-based composite system. The sintering aid composition acts as a temporary facilitator that enables low-temperature processing, and the final product achieves the desired performance without requiring the expensive aluminum nitride raw materials or costly reducing atmosphere processing conditions.
3Ease of manufacture
If sintering aid is added to alumina to enable sintering at high temperature, then ease of manufacture is improved, but thermal conductivity decreases from typical range of 18-23 W/m·K
Solution Approach 1:
The patent changes the composition parameters of the sintering aid from conventional single-oxide aids to specific multi-oxide combinations (Y2O3-Al2O3, Nb2O5-Al2O3, Ta2O5-Al2O3 systems with controlled ratios). This compositional parameter change enables the sintering aid to promote densification while having minimal negative impact on thermal conductivity, achieving a balance between processability and thermal performance.
4Stability of the object's composition
If aluminum nitride is sintered in reducing atmosphere (nitrogen or hydrogen-nitrogen mixed gas) to prevent oxidation, then material stability is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent uses an inert or neutral atmosphere (air or ordinary atmosphere) during sintering instead of requiring complex reducing atmospheres. The sintering aid composition protects the alumina material from oxidation and enables stable sintering in simpler atmospheric conditions, thereby reducing manufacturing process complexity while maintaining material stability.
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 composite ceramic exhibits improved mechanical strength and thermal conductivity, with flexural strengths up to 722 MPa and thermal conductivities ranging from 19 to 23 W/m·K, making it suitable for electronic device substrates without the high costs associated with aluminum nitride.
Implementation Method 1
graphene oxide; and carbon nanotubes... good thermal conductivity... thermal conductivities ranging from 19 to 23 W/m·K
Implementation Method 2
zirconia (ZrO2) or yttria-stabilized zirconia... excellent mechanical strength... flexural strengths up to 722 MPa
Implementation Method 3
mixed and sintered at reduced temperatures... sintering was performed at a temperature of 1,700° C. to 2,200° C.
Data Source
AI summary
Provided is an alumina composite ceramic composition which has electrical insulation properties as well as better mechanical strength and thermal conductivity than a typical alumina-based material. Thus, the alumina composite ceramic composition is promising for a material of a substrate or an insulating package of an electronic device. The alumina composite ceramic composition of the present invention may include alumina (Al2O3), zirconia (ZrO2) or yttria-stabilized zirconia as a first additive, and graphene oxide and carbon nanotubes, as a second additive. In this case, in consideration of two aspects of sinterability and electrical resistivity characteristics of the alumina composite ceramic composition, the graphene oxide may be appropriately adjusted to be in the form of a graphene oxide phase and a reduced graphene phase which coexist in the alumina composite ceramic composition.