Theoretical Strategy for Interface Design and Thermal Performance Prediction in Diamond/Aluminum Composite Based on Scattering-Mediated Acoustic Mismatch Model

At a Glance

Metadata	Details
Publication Date	2023-06-06
Journal	Materials
Authors	Zhiliang Hua, Kang Wang, Wenfang Li, Zhiyan Chen
Institutions	Dongguan University of Technology, Central South University
Citations	6
Analysis	Full AI Review Included

Technical Documentation & Analysis: Interface Engineering for High-Performance Diamond Composites

Reference Paper: Theoretical Strategy for Interface Design and Thermal Performance Prediction in Diamond/Aluminum Composite Based on Scattering-Mediated Acoustic Mismatch Model (Materials 2023, 16, 4208).

Executive Summary

This research provides critical theoretical insights into optimizing diamond/aluminum (Al) composites for advanced thermal management applications by controlling the interfacial thermal conductance (ITC).

Core Value Proposition: Utilizes the Scattering-Mediated Acoustic Mismatch Model (SMAMM) and Differential Effective Medium (DEM) model to predict the thermal conductivity (TC) of diamond/Al composites featuring various nanoscale interfacial layers.
Key Mechanism: Confirms that interfacial layers with high intrinsic TC, high phonon velocity, and high Debye temperature are essential for establishing a favorable phonon gradient, thereby suppressing scattering and maximizing heat transfer.
Optimal Interlayer Identification: Silicon Carbide (SiC) was identified as the most promising interfacial layer, achieving a predicted TC of 848.5 W/mK for the composite (250 nm layer, 50 vol.% diamond).
Thickness Dependence: Demonstrates a critical relationship between layer thickness and thermal performance; nanoscale layers (e.g., 1 nm Al₄C₃) significantly reduce Interfacial Thermal Resistance (ITR), while thicker layers (e.g., 500 nm) generally degrade performance.
Carbide Transformation: Analyzes the effect of carbide conversion percentage, showing that full conversion (100% SiC) yields superior results compared to mixed metal/carbide interfaces.
6CCVD Relevance: The findings directly validate the necessity of high-purity, custom-metallized MPCVD diamond substrates (SCD or PCD) for achieving predictable and high-performance thermal interfaces in microelectronics and semiconductor packaging.

Technical Specifications

The following hard data points were extracted from the theoretical modeling and reference material, highlighting the critical parameters for high-performance diamond/Al composites.

Parameter	Value	Unit	Context
Diamond Intrinsic Thermal Conductivity (K)	1800	W/mK	Reinforcing phase baseline
Aluminum Intrinsic Thermal Conductivity (K)	237	W/mK	Matrix baseline
Diamond Debye Temperature (θ_d)	2230	K	Highest phonon energy material
SiC Intrinsic Thermal Conductivity (K)	179	W/mK	Optimal carbide layer intrinsic TC
SiC Debye Temperature (θ_d)	1300	K	High phonon energy for intermediate layer
Diamond Volume Fraction (V_r)	50	vol.%	Used in Differential Effective Medium (DEM) model
Diamond Particle Size (a)	150	µm	Used in DEM model calculation
Predicted Composite TC (Si-SiC Optimal)	848.5	W/mK	250 nm layer, 100% SiC conversion
Predicted Optimal ITC (Si-SiC Optimal)	4.68 x 10⁸	W/m²K	Interfacial Thermal Conductance
Experimental ITR (Diamond/Al, Baseline)	5.43 x 10^-9	m²K/W	Thermal Boundary Resistance (Reciprocal of ITC)
Predicted ITR (Al₄C₃/Al, 1 nm layer)	1.08 x 10^-9	m²K/W	Demonstrates benefit of nanoscale layer

Key Methodologies

The theoretical analysis relied on a multi-layer interface model combined with advanced phonon transport models to predict thermal performance at room temperature.

Interface Structure Modeling: The composite interface was simplified into a multi-layer structure consisting of Diamond, Carbide (C), Metal (M), Intermetallics (I), and Aluminum Matrix. Calculations were simplified by assuming the metal coating did not react with the aluminum matrix (no intermetallic formation).
Thermal Resistance (R_b) Formulation: The total thermal resistance (R_b) was established as the sum of interfacial thermal resistance (R_interface) and the intrinsic thermal resistance (R_resistance) of the interface layers themselves.
ITC Calculation via SMAMM: Interfacial Thermal Conductance (ITC, h_c) between adjacent phases (e.g., h_D-C, h_C-M) was calculated using the Scattering-Mediated Acoustic Mismatch Model (SMAMM).
- SMAMM Assumptions: Phonons were assumed to be the dominant heat carriers; diffuse scattering at the interface was ignored; mode conversion was ignored.
- Input Parameters: Calculations required material density, specific heat, phonon velocity, and Debye temperature (Table 1).
TC Calculation via DEM: The overall Thermal Conductivity (TC, K_c) of the diamond/Al composite was predicted using the Differential Effective Medium (DEM) model, incorporating the calculated ITC (h_c), diamond volume fraction (50 vol.%), and particle size (150 µm).
Parametric Study: The models were used to evaluate the impact of two primary variables on TC and ITC:
- Interface layer thickness (ranging from 0.01 µm to 2.0 µm).
- Carbide conversion percentage (ranging from 0% to 100%) for 250 nm thick layers.

6CCVD Solutions & Capabilities

This research confirms that precise control over the diamond surface and the subsequent interfacial layer is paramount for achieving high thermal performance in metal matrix composites. 6CCVD is uniquely positioned to supply the foundational MPCVD diamond materials and the necessary surface engineering required to replicate and advance this theoretical work.

Applicable Materials

To replicate or extend this research, engineers require high-pquality, high-purity diamond material that can withstand high-temperature processing and surface modification.

6CCVD Material Recommendation	Rationale & Application
Optical Grade Single Crystal Diamond (SCD)	Provides the highest intrinsic thermal conductivity (up to 2000 W/mK), minimizing the thermal resistance of the diamond phase itself. Ideal for high-end heat spreaders and devices where maximum TC is required.
High-Purity Polycrystalline Diamond (PCD)	Available in large formats (up to 125 mm diameter) and thicknesses up to 500 µm. Excellent for scaling up thermal management solutions where large-area coverage is necessary.
Custom Substrates (up to 10 mm thick)	For specialized thermal sinks or structural components requiring robust diamond reinforcement.

Customization Potential

The paper emphasizes the critical role of nanoscale layer thickness (0.01 µm to 0.5 µm) and specific carbide-forming metals (Si, B, Cr, Ti, W). 6CCVD offers comprehensive services to meet these precise requirements.

Custom Metalization Services: 6CCVD provides in-house deposition of critical carbide-forming elements identified in the study, including Ti, W, and Cu. We also offer custom metal stacks (e.g., Ti/Pt/Au) and can assist in developing precursors for Si and B layers necessary for SiC and B₄C formation.
Thickness Control: We guarantee precise control over deposited layer thickness, essential for achieving the optimal nanoscale interfaces (e.g., 50 nm or 250 nm) studied in the SMAMM/DEM models.
Surface Preparation: Our advanced polishing capabilities (Ra < 1 nm for SCD, Ra < 5 nm for inch-size PCD) ensure an atomically smooth diamond surface, which is crucial for predictable and uniform interfacial layer formation and subsequent thermal performance.
Custom Dimensions: We supply diamond plates and wafers in custom dimensions up to 125 mm (PCD), enabling the fabrication of large-scale thermal management components.

Engineering Support

Translating theoretical models like SMAMM and DEM into reliable fabrication processes requires deep material science expertise.

Interface Design Consultation: 6CCVD’s in-house PhD engineering team specializes in diamond surface chemistry and interface design. We can assist researchers and engineers in selecting the optimal diamond grade, metalization stack, and processing parameters (e.g., temperature, pressure) to achieve the desired carbide conversion and minimize Interfacial Thermal Resistance (ITR) for similar Diamond/Metal Matrix Composite projects.
Global Logistics: We ensure reliable global shipping (DDU default, DDP available) of high-value diamond materials, supporting international research and manufacturing supply chains.

For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.

View Original Abstract

Inserting modification layers at the diamond/Al interface is an effective technique in improving the interfacial thermal conductance (ITC) of the composite. However, few study reports the effect of interfacial structure on the thermal conductivity (TC) of diamond/Al composites at room temperature. Herein, the scattering-mediated acoustic mismatch model, suitable for evaluating the ITC at room temperature, is utilized to predict the TC performance of the diamond/Al composite. According to the practical microstructure of the composites, the reaction products at diamond/Al interface on the TC performance are concerned. Results indicate that the TC of the diamond/Al composite is dominantly affected by the thickness, the Debye temperature and the TC of the interfacial phase, meeting with multiple documented results. This work provides a method to assess the interfacial structure on the TC performance of metal matrix composite at room temperature.

Tech Support

Original Source

DOI: https://doi.org/10.3390/ma16124208

References

2006 - High-performance Thermal Management Materials
2011 - Review of metal matrix composites with high thermal conductivity for thermal management applications [Crossref]
2013 - The role of Ti coating in enhancing tensile strength of Al/diamond composites [Crossref]
2015 - Effect of metal matrix alloying on mechanical strength of diamond particle-reinforced aluminum composites [Crossref]
2016 - Effect of diamond surface chemistry and structure on the interfacial microstructure and properties of Al/diamond composites [Crossref]
2006 - Interface formation in infiltrated Al (Si)/diamond composites [Crossref]
2004 - Microstructure and interfacial characteristics of aluminium-diamond composite materials [Crossref]
2013 - Fabrication of diamond/aluminum composites by vacuum hot pressing: Process optimization and thermal properties [Crossref]
2022 - Realizing ultrahigh thermal conductivity in bimodal-diamond/Al composites via interface engineering [Crossref]