New Energy Fuse Ceramic Body

 

The ceramic body forms the electrical insulating and mechanical enclosure around the fuse element. Its material and geometry must suit the fuse's operating voltage, rated current, fault conditions, thermal environment, and assembly design. A ceramic body is not a universal component: the required wall thickness, internal diameter, creepage geometry and end interface depend on the complete fuse specification.

Alumina Composition and Material Selection
Alumina (Al₂O₃) is used in electrical ceramic components where electrical insulation, thermal stability and mechanical strength are required. Depending on the product specification, the material may be selected at different purity levels. Apollo's published energy-storage fuse ceramic range lists alumina options from 75% to 99.9%, alongside other ceramic materials. This is a range of material options, not a claim that every product uses 95% alumina.

Material selection should consider:
Alumina content and impurities: Composition affects electrical, thermal, and mechanical properties.
Thermal expansion: The coefficient of thermal expansion influences compatibility with metal end caps and brazed interfaces.
Porosity and density: Incomplete densification can affect strength and insulation performance.
Wall thickness and geometry: The body must accommodate the fuse element, internal filler, and required insulation distances.
Surface condition: Glazing, polishing, or grinding may be specified according to sealing, assembly, and electrical requirements.

 

Forming and Dimensional Control
Ceramic body manufacturing can involve extrusion, dry pressing or isostatic pressing, depending on cross-section, length, dimensional requirements and production volume. After forming, controlled drying and sintering establish the ceramic structure. Secondary grinding, drilling, threading, or end-face finishing may be required to meet the finished drawing.

 

Unlike metal stamping, ceramic forming must account for shrinkage during sintering. The green-body dimensions cannot be treated as finished-part dimensions. Tool compensation should be based on the actual material system and validated process conditions.

 

For tubular bodies, the inner diameter, outer diameter, wall thickness, concentricity, and end-face squareness are important. Thin walls may reduce the available mechanical margin, while excess wall thickness can change the internal volume and assembly fit. The design should therefore define critical dimensions rather than relying on a general tolerance for every feature.

Ceramic Body Technical Specifications

 

Parameter	Reference specification	Engineering verification
Ceramic material	Alumina (Al₂O₃), 75%–99.9% options listed for the product range	Material grade and supplier documentation
Ceramic density	Product listing specifies above 3.65 g/cm³ for the referenced energy-storage range	Density test method and material specification
Outer diameter (OD)	±0.05 mm listed as an available option	Drawing-based dimensional inspection
Inner diameter (ID)	±0.10 mm listed as an available option	Bore gauge, optical measurement, or suitable calibrated gauge
Ceramic shape	Round, square, oval, or half-tube options	Drawing and first-article inspection
Forming method	Extrusion, dry pressing or isostatic pressing, as applicable	Process validation
Surface finish	Polished or glazed options	Visual and dimensional inspection
Secondary machining	Fine grinding or threading where required	Feature-specific dimensional verification
Dielectric strength	Defined by the material grade, geometry, and test method	Specified dielectric test
Thermal shock resistance	Defined by the application and qualification procedure	Thermal-cycle or thermal-shock testing

 

The dimensional options and forming methods above are based on the published energy-storage fuse ceramic product listing. They should not be assumed to apply to every product in the category.

 

For material-specific requirements, see 95% Alumina Ceramic.

 

 

The joining requirements of a ceramic fuse body depend on the end-cap design and whether the assembly uses mechanical retention, metallization, or a ceramic-to-metal brazed joint. A plain ceramic tube does not automatically require metallization or brazing. These processes should be specified only where the product architecture requires them.

Ceramic-to-Metal Joining
For metallized ceramic components, a compatible metal layer may be applied to a defined area before joining. Mo-Mn metallization is one established route for certain alumina-to-metal assemblies, often followed by a suitable finishing layer and brazing process. The metallization system, surface preparation, and joining cycle must be compatible with the ceramic composition and metal terminal.

 

Thermal expansion mismatch between ceramic and metal can create residual stresses during cooling and subsequent operation. Joint design should account for the geometry, joining temperature, service temperature range, and mechanical loads. Where a brazed joint is part of the design, inspection should target interface continuity, cracks, incomplete bonding, and other specified defects.

Glazing, Grinding and Surface Protection
Glazing can be specified where a controlled surface finish or environmental barrier is required. Precision grinding may be used to control the inner diameter, outer diameter, end faces or mounting features. These operations must not introduce edge chipping, surface cracks or unacceptable residual damage.

 

Inspection requirements may include:
Surface examination for cracks, chips and visible defects.
Measurement of critical bore and end-face dimensions.
Verification of coating or glaze coverage where specified.
Dielectric testing using the agreed electrode arrangement and test conditions.
Joint inspection for metallized or brazed designs.

 

Request Custom Technical Evaluation

 

 

Quality control for ceramic fuse bodies should cover raw material identification, forming, sintering, secondary machining, and final inspection. The control plan must distinguish process variables from finished-part acceptance criteria. A dimension that is achievable on a machined feature may not be suitable as a general tolerance for an as-sintered surface.

Inspection of Ceramic Fuse Bodies
Incoming material verification should confirm the specified ceramic grade and the applicable supplier documentation. During forming and sintering, process monitoring should address dimensional shrinkage, density consistency, and visible defects. After finishing, the inspection plan should focus on the dimensions that affect fuse assembly, sealing, and insulation distances.

 

Depending on the product drawing and quality agreement, inspection may include:
OD, ID and wall-thickness measurements.
End-face geometry, flatness and concentricity checks.
Visual examination for cracks, chips, warpage and surface defects.
Density or material verification where required.
Dielectric withstand testing using the specified voltage, duration, and test fixture.
Thermal-cycle or thermal-shock qualification for the intended service environment.
Inspection of metallized or brazed interfaces where applicable.

X-ray inspection, CMM measurement and other specialized methods should be specified only when the part geometry, defect risk and actual inspection capability justify their use. The measurement method must be appropriate for brittle ceramic components and the feature being assessed.

Quality Documentation and Supplier Approval
Apollo identifies ISO 9001 and IATF 16949 within its published quality and certification information. The certificate validity, certified entity, manufacturing location, and scope should be verified for the particular supply project before the credentials are used in customer-facing claims.

For automotive or other controlled procurement programs, PPAP Level 3 documentation may be agreed where the customer requires it. A submission package may include:

Process flow diagram.
Process Failure Mode and Effects Analysis (PFMEA).
Control plan.
Material and dimensional records.
Applicable performance test reports.
Process capability evidence for designated critical characteristics.

PPAP documentation does not replace product-specific validation. Dielectric performance, mechanical integrity, and the complete fuse's interruption rating must be evaluated against the relevant customer specification and applicable fuse standard.

 

Packaging and Batch Identification
Ceramic components are brittle and can be damaged by point loading, edge impact, or vibration during transportation. Packaging should separate individual parts, prevent direct ceramic-to-ceramic impact and protect finished end faces. Lot labels should connect the shipment to the applicable part number, revision, and inspection records.

 

For recurring production, the control plan should define how changes to ceramic composition, tooling, sintering conditions, or secondary machining are reviewed before implementation. This reduces the risk of unapproved changes affecting dimensional fit or electrical performance.
 

 

 

Send Apollo your 2D drawing, 3D CAD model, or existing ceramic sample details for a manufacturing review. Include the target application (EV, PV or energy storage), ceramic grade, OD/ID dimensions, wall thickness, end-interface design and required electrical or mechanical qualification criteria.

 

For ceramic-to-metal assemblies, also specify metallization, brazing, or other joining requirements. These details allow the engineering team to evaluate material selection, forming and sintering allowances, secondary machining, inspection methods, and packaging requirements before quotation.

 

Request a drawing-based DFM review and factory quotation. A preliminary review within 24 hours can be targeted for complete inquiries; timing depends on drawing complexity, material availability, and the information supplied.