Antimony-Impregnated Graphite M106D Explained: Density 2.20 g/cm³, Compressive Strength 190 MPa and Hot Oil Pump Applications Above 400°C

Antimony-impregnated graphite M106D is the answer where resin-impregnated graphite fails at high temperature. Huahao Sealing's measured data for M106D: density 2.20 g/cm³, compressive strength 190 MPa. Behind these two numbers lies the essential difference between metal and resin impregnation. This article explains where M106D's performance comes from, its limits, and what it replaces.

1. M106D Data and What It Means

M106D uses a high-strength carbon graphite base impregnated with antimony under vacuum and pressure. Key data:

• Density 2.20 g/cm³: clearly above the 1.75-1.90 g/cm³ range of resin-impregnated graphite, showing the pores are densely filled with metal
• Compressive strength 190 MPa: above the common 150-180 MPa range of resin-impregnated grades, with better resistance to crushing and deformation
• Porosity below 2% after impregnation: the baked base starts at 10%-20% porosity; antimony fills the micropores
• Temperature resistance above 400°C: antimony melts at about 630°C, far above the 150-200°C service ceiling of resins

Density and compressive strength are the two properties you can re-verify on receipt — water displacement and a compression tester are enough. This is the most direct way for buyers to check incoming material.

2. Metal vs Resin Impregnation: The Essential Difference

The difference is not which fills better, but the nature of the filler.

2.1 Resin Impregnation: Organic Pore Sealing

Resin cures inside the pores as a polymer; its job is sealing. Its temperature limit is the resin's own thermal decomposition: phenolic, epoxy and furan serve long-term at 150-200°C. Overheat and the resin decomposes, pores reopen, and leakage and wear worsen together. Resin impregnation's value lies in its chemical resistance spectrum and cost.

2.2 Antimony Metal Impregnation: Metal Load Sharing

Antimony fills the pores as a metal and shares structural load. Three essential differences:

1.Temperature: antimony melts at about 630°C, with no resin-type decomposition, so the ring serves above 400°C along with the base

2.Strength: the metal network raises overall compressive and flexural capacity — the measured 190 MPa compressive strength comes from this

3.Wear: the metal phase forms supporting points on the friction face; the dry friction coefficient stays within 0.04-0.15, but wear rate is clearly lower than resin-only parts

The trade-offs are cost and chemical spectrum: antimony resists strong oxidizing acids poorly and costs more than resin. So M106D is not a universal grade — it is the dedicated answer for high-temperature, high-pressure duty.

3. Where M106D Fits — and Where It Does Not

Suitable:

• Hot oil pumps and thermal oil circulation pumps at 300-450°C where resin parts inevitably fail — M106D is the standard choice
• Boiler feed pumps and high-temperature steam environments with both temperature and pressure elevated
• Media with higher solids content and abrasiveness, where the metal phase outwears resin
• Dry running or poorly lubricated duty: graphite self-lubrication plus metal support outperforms resin parts

Not suitable:

• Strong oxidizing acids (hot concentrated nitric or sulfuric acid): both antimony and graphite corrode; choose PTFE or special resin impregnation
• Ordinary water and mild media below 150°C: resin impregnation is more economical — do not pay for temperature resistance you do not need

4. Summary

The selection logic for M106D in one sentence: when temperature exceeds 200°C or abrasiveness dominates, use antimony impregnation; otherwise resin is more economical. Huahao Sealing was founded in 2006 with its factory in Lu'an, Anhui. Every batch of M106D antimony-impregnated rings is tested for density and compressive strength, and non-standard sizes are made to customer drawings. If your hot oil pump seals keep failing, send the media temperature and pressure to the manufacturer for a material matching analysis before ordering.