HX AP-17 Basic zinc orthophosphate & molybdenum hydrate

What Is HX AP-17 Basic Zinc Orthophosphate & Molybdenum Hydrate

HX AP-17 is a molybdenum-modified zinc phosphate anti-corrosion pigment featuring narrow particle size distribution, uniform particle morphology, and outstanding resin compatibility. The molybdenum modification is the key — molybdate ions provide balanced corrosion inhibition across all three service stages: rapid early-stage passivation, sustained mid-stage active protection, and stable late-stage barrier performance. This three-phase protection profile makes AP-17 uniquely suited for applications where coating integrity must be maintained over decades, not years. With the lowest oil absorption in the series (14-29 g/100g), tightest particle size (D50: 1.0-5.0 μm), and excellent compatibility across all binder chemistries, AP-17 solves the formulator’s dilemma — maximum protection without compromising application properties.

Key Features

• Molybdenum-Modified Chemistry — Molybdate ions provide three-stage corrosion inhibition: early passivation → mid-stage active protection → late-stage barrier stability
• Lowest Oil Absorption in Series (14-29 g/100g) — Minimum binder demand for maximum formulation freedom
• Finest Particle Size (D50: 1.0-5.0 μm) — Suitable for the thinnest high-performance coating films without surface defects
• Uniform Particle Morphology — Consistent particle shape ensures predictable dispersion behavior and batch-to-batch reproducibility
• Outstanding Resin Compatibility — Validated across alkyds, acrylics, epoxies, polyesters, and polyurethanes without viscosity or stability issues
• Universal Recommended Rating — All application categories rated Recommended excluding automotive OEM/refinish

Recommended Applications

✅ Recommended  |  ⚪ Suitable  |  ❌ Not Recommended

Technical Data

Packaging

25 kg/bag. Custom packaging available upon request.

Frequently Asked Questions

What does molybdenum modification add over standard zinc phosphate?

Molybdate ions (MoO₄²⁻) provide a unique three-phase corrosion inhibition profile. In the early stage (first hours after application), they rapidly adsorb onto the metal surface and initiate passivation — faster than phosphate alone. In the mid-stage (days to weeks), they form a mixed Mo-P-Fe complex layer that actively blocks corrosion propagation even if the coating is mechanically damaged. In the late stage (months to years), the molybdate component stabilizes the passivation film against pH fluctuations and chloride attack, which are the primary causes of long-term coating failure in industrial and marine environments. This three-phase mechanism is why AP-17 is specified for applications requiring 15-25 year service lifetimes.

Why is AP-17’s particle size (D50: 1.0-5.0) important?

At D50 below 5 μm, the pigment can be used in coatings applied at 15-20 μm dry film thickness without visible particles or surface roughness. This opens up applications in coil coatings, can coatings, and thin-film automotive primers where traditional anti-corrosion pigments (typically D50 5-10 μm) would cause surface defects or require thicker films. The narrow distribution also means more consistent performance — fewer oversized particles that could act as corrosion initiation sites.

Is the molybdenum content environmentally regulated?

Molybdenum-based pigments have a favorable environmental profile compared to chromate or high-zinc alternatives. Molybdenum is an essential trace element, not a heavy metal of concern under REACH or RoHS. AP-17’s molybdenum content is well below regulatory thresholds and the pigment is classified as non-toxic and non-hazardous for transport. Full regulatory documentation is available on request.

Disclaimer — This Technical Data Sheet reflects our best understanding of typical product properties at the time of publication. Listed values are representative of standard production and are not intended as specifications, contractual parameters, or fitness guarantees. Batch variations within normal manufacturing tolerances may occur; users should verify critical parameters against their own requirements before use. Processing methods, formulations, and end-use environments are beyond the manufacturer’s control. The buyer assumes full responsibility for confirming product suitability through its own testing and quality assurance. No intellectual property license is granted or implied. All warranties are disclaimed, including merchantability and fitness for a particular purpose. The manufacturer is not liable for incidental, consequential, or special damages. All sales are governed by the manufacturer’s standard terms, available upon request. This product may contain particles below 0.1 μm.