详情描述

Thermal properties: Coefficient of thermal expansion and thermal stability

Thermal expansion coefficient (CTE) regulation:

Product CTE can be controlled at2.0~3.0×10⁻⁶/K（25~300℃）Highly matched with diamond CTE (≈1×10⁻⁶/K). After sealing, the interfacial thermal stress is significantly reduced, preventing microcracks or delamination caused by temperature cycling (such as device start/stop, environmental temperature differences).

Glass Transition and Sealing Temperature:

Glass softening point reduced to 450~550℃Sealing process temperature requirements500~650℃(Well below the typical borosilicate glass range of 700-900°C.) The low-temperature characteristics reduce the risk of diamond thermal damage (diamonds are prone to graphitization at high temperatures), while also lowering energy consumption and improving production efficiency.

2. Melt and rheological properties

Melt Viscosity Compatibility:

The melt viscosity is within 10³~10⁴ Pa·s at sealing temperature (optimal wetting range). The glass can uniformly "spread" on the diamond surface, filling microscopic pores to form a defect-free, tight sealing layer. 

Powder processing properties:

Product isWhite fine powder (D50: 5~15μm, customizable)，Good flow, no cakingAfter adding organic binder (such as terpene alcohol), it is easily adjustable into a paste form, meeting the requirements for precise coating processes like spraying and screen printing. 

3. Mechanical Properties

Sealing Strength:

Fused glass and diamond are bonded through chemical and physical anchoring, creating a strong interface. The tensile and shear strength of the sealant is over 30% higher than that of traditional glass (actual values can reach 15~25MPa, slightly adjusted by formula). 

Hardness and wear resistance:

Sealing layerVickers hardness ranging from 400 to 500 HVExcellent wear resistance, maintaining interface structure integrity over a long period.

Chemical Properties


Chemical Stability

Acid and alkali resistance:

Glass exhibits no significant corrosion in acidic or alkaline environments with pH levels between 2 and 12 (loss in mass < 5%), meeting the requirements for humid and corrosive industrial conditions. 

Antioxidant properties:

Boron oxide (B₂O₃)-constructed glass networks remain stable at high temperatures (≤800℃), without crystalline precipitation or phase separation, ensuring the chemical inertness of the sealing layer during long-term service.

2. Interface Reactivity

During sealing, a controlled chemical reaction occurs between the glass composition and the diamond surface.

The role of boron oxide (B₂O₃):

At high temperatures, B₂O₃ reacts with adsorbed oxygen and dangling bonds on the diamond surface to form B-O-C covalent bonds, achieving chemical bonding; simultaneously, B₂O₃ fills the micro-defects on the diamond surface, enhancing physical anchoring. 

Lithium Oxide (Li₂O) and Sodium Oxide (Na₂O) applications:

As a "network modifier," it breaks Si-O-Si bonds, reduces glass viscosity, and enhances the wettability and penetration of the melt onto the diamond surface; simultaneously, Li⁺/Na⁺ ions statically adsorb to the polar groups (e.g., -OH) on the diamond surface, aiding in interfacial bonding.

Principle of Diamond Sealing


1. Thermal expansion match: Eliminate thermal stress

Diamond has an extremely low CTE (≈1×10⁻⁶/K), whereas metal/ ceramic substrates have a higher CTE (e.g., stainless steel CTE ≈ 12×10⁻⁶/K). By adjusting the glass CTE (2.0~3.0×10⁻⁶/K), it can be positioned between diamond and the substrate, creating a "CTE gradient buffer layer":

As temperature rises, substrate expansion > glass layer > diamond; the glass layer is under pressure.

As the temperature drops, the substrate shrinks more than the glass layer and diamond, causing the glass layer to be stretched.

The glass layer absorbs thermal expansion differences through elastic deformation, preventing cracking at the interface due to concentrated thermal stress.

2. Surface Wetting and Spreading: Physical + Chemical Synergy

Physical Wetting:

Low-temperature melt (500~650℃) has low viscosity and small surface tension (about 0.4~0.6 N/m), which can spontaneously spread on diamond surfaces, filling micrometer-scale roughness (Ra<0.5μm) pores, and forming a mechanical interlocking structure.

Chemical Wetting:

Glass components (B₂O₃, Li₂O, etc.) undergo chemical reactions with the diamond surface, reducing the solid-liquid interface energy (from ≈0.8 N/m to ≈0.3 N/m), and lowering the contact angle from >90° (non-wettable) to <30° (fully wettable), achieving molecular-level adhesion.

3. Interface Integration: Chemically Bonded Leadership

At high temperatures, a "transition layer" forms between the glass and diamond surfaces: 

Carbon atoms on the diamond surface form B-O-C covalent bonds with B and O atoms in B₂O₃.

Li₂O, Na₂O release Li⁺/Na⁺, which form ionic/coordination bonds with the polar groups (e.g., C-OH) on the diamond surface.

This "chemical bonding + physical anchoring" composite mechanism enables the sealing strength to exceed the limit of physical adsorption (usually <5MPa) and reach engineering application levels (15~25MPa).

Characteristics - Synergistic Logic of Principles

Borosilicate glass powder addresses the three major pain points of diamond sealing through the logical sequence of "component regulation → targeted design of physical and chemical properties → synergistic combination of multiple mechanisms at the interface."

Thermal matching (CTE gradient buffer) → Eliminates thermal stress, enhances long-term reliability.

Process compatibility (low temperature, low viscosity) → Compatible with diamond thermal sensitivity, achieving efficient sealing.

Strong interface integration (chemical bonding + physical anchoring) → Breaks through strength bottleneck, meets scenario requirements.