An accelerated laboratory corrosion test developed by Renault

Introduction

Originally developed in the late 1990’s, the Renault cyclic corrosion test, officially D17 2028, is universally known as the ECC-1 test (from the French; Essai de Corrosion Cyclique 1).

This test comprises of a multi-function cycle, during which test samples are exposed to a complex sequence of precisely controlled climatic conditions. This sequence is then repeated a number of times. 

Test Conditions

Compared to traditional salt spray fall-out rates of 1.5ml per hour per 80cm2, with a control accuracy of ±33% tolerance, the ECC-1 salt spray fall-out rate is much higher at 5ml per hour per 80cm2, with a tighter than usual control accuracy of ±20%. It also uses a much weaker electrolyte of approximately 1% NaCl.

The test temperature required is a continuous +35°C with a control accuracy of ±2.5°C during humidity transitions and ±1.0°C during constant humidity control. The test humidity required varies between 20, 55 & 90%RH, with a control accuracy of ±5% at 20%RH, and ±3% at 55 & 90%RH.

These conditions must be verified using independent, calibrated instrumentation, measured over a wide range of horizontal and vertical points inside the chamber. In addition to these demanding control requirements, the ECC-1 test also requires automatic purging and rinsing of the chamber interior, after the salt spray phase.

Method

Specimens are placed in the chamber and subject to a series of distinctive phases, the pre-conditioned temperature of 35°C should be maintained throughout.

• Pre-conditioning of the chamber to a temperature of 35°C, with controlled humidity of between 90%RH and 98%RH (non-saturated). 
• Exposure test samples to 30 minutes to salt spray falling onto the samples under gravity.
• A 5 minute system flush with forced air to remove residual salt mist from the chamber.
• A 5 minute internal wall rinse phase with demineralised water to rinse any salt spray residue from the inner walls of the chamber remaining from the salt spray phase.
• A further second 5 minute system flush with forced air.
• 1 hour 40 minutes of forced air drying with controlled humidity of 20%RH.
• 1 hour 35 minutes of further drying at a controlled humidity of 55% RH.
• Controlled humidity of 90% RH for 1 hour 20 minutes.
• Controlled humidity of 55% RH for 2 hours 40 minutes.

For a single test the last 2 stages should be repeated, ensuring a minimum test duration of 12 hours. 

Typical Application

Developed by Renault EEC-1 is an integral part of their internal development and supplier Quality Control & Auditing processes.

If you would like further information please call our experienced team on 01827 318040 or email sales@ascott-analytical.com