Material Process

Material Process of SMT Nozzles

Since the melting points of the nozzle components such as tungsten carbide (WC), zirconia (ZrO2) are too high and the reaction occurs when melting such as dissolution and precipitation between diamond (carbon) and cobalt (Co), PM is a feasible process to use.

Nozzle Tip – Powder Metallurgy (PM)
Nozzle Body – PM or use general steel alloys such as stainless steel.

1. Introduction of Powder Metallurgy (PM)

PM Process

Pressing - Powders are compressed into the desired shape in a press-type machine using punch-and-die tooling designed specifically for the part.
Sintering - Heating at a temperature well below melting.


Near-net shape, No waste, Controlled porosity, Dimension control better than casting


High cost of tooling and powder, Powder Harder to handle Geometric & Size limitation, Density variation

Particle Shapes and Sizes

Particle Shapes and Sizes

Morphology (Particle Shapes)


2. PM materials for SMT nozzles

Various materials can be adopted for forming a nozzle tip or a nozzle body:
Principal component: polycrystalline diamond (PCD), monocrystal diamond, diamond created by physical vapor deposition (PVD), diamond created by chemical vapor deposition (CVD), diamond like carbon (DLC), carbonado, cubic boron nitride (CBN), hexagonal boron nitride, zirconia, or a combination of these
Refractory component: tungsten carbide, titanium carbide, tantalum carbide, zirconium carbide, hafnium carbide, chromium, titanium, vanadium, niobium, aluminum, nickel, hafnium, silicon, tungsten, molybdenum, or alloys including one or more of these
Solvent-Catalyst Metal (binder): cobalt

Considered material properties: Modulus, Coefficient of Thermal Expansion (CTE), Dilatoric and Deviatoric Stresses, Free Voulume Reduction of each powder, etc.

Material Properties
Material Specific Gravity Hardness (Knoop) Thermal Conductivity (W/m K) CTE (x10-6)
Sintered Polycrystalline Diamond (PCD) 3.5 - 4.0 7000 900 1.5 - 4.8
Cubic Boron Nitride (CBN) 3.48 4500 800 1.0 - 4.0
Zirconia (ZrO2) 3.5 3000   7.8 - 8.8
Tungsten Carbide (WC) (10% Co) 14.6 2200 112 4 - 6

Requested purposes for SMT nozzle tips

Abrasive resistance and Hardness, Impact strength and Toughness, Whitening event (to reduce)

* Whitening event: As being used, a nozzle tip turns from black to white due to wearing, contaminating by solder paste.





Whitening event

Whitening event

3. CROSTU's SMT Nozzle Materials & PM Process

Crostu's SMT nozzle materials
SMT nozzle materials
Type Components Production Process
Nozzle Tip Diamond Tip PCD + Carbide, Cobalt, etc. PM
CBN Tip CBN + Ceramic, Carbide, Cobalt, etc. PM
Ceramic Tip Zirconia + Carbide, Cobalt, etc. PM
Nozzle Body Superhard material Tunsten carbide + Cobalt PM
Steel Alloys Stainless steel or others Ingot material

SMT nozzle PM Process

Raw materials (PCD, WC, Co) → Milling → Drying → CIP (Shrinkage rate, Dimension) → Sintering (Hot Isostatic Pressing, HIP) → Machining → Nozzle tip disc / Nozzle body rod

Sintering mechanism

Nozzle sintering mechanism

PM products

PM nozzle tip disc

Nozzle tip disc

Nozzle tip after finishing machining

Nozzle tip after machining tip disc

Nozzle body rods

Nozzle body rods