"material decay" is correct and usable in written English.
You can use it to refer to the deterioration of an object (material) due to age, the environment, or wear and tear. For example, "The old building was suffering from material decay, with the walls crumbling and paint peeling off."
For him, the material decay of Rome was the effect and symbol of moral decadence.
Holding on to pictures was, for most of the history of photography, a matter of material decay and physical storage.
The material decay that had inspired him in Rome was the effect and symbol of moral decadence.
On the other hand, ductility, toughness and strength of the material decay during hydrolytic degradation.
The conservator of paintings aims above all at "true conservation," the preservation of the objects in conditions that, as far as possible, will arrest material decay and delay as long as possible the moment when restoration is needed.
Bridges over the Milano-Meda highway outside Milan are also under observation, both for material decay and for problems related to heavy goods vehicles in Italy's most industrialised area.
When this material decays under water, in the absence of oxygen, the carbon content increases.
An earlier plan backed by the Energy Department called for leaving the reactor on the lab grounds until the radioactive material decayed, which would take 87,000 years.
Such rapid growth, it argues, will create intractable problems for people's health and the environment as the waste, much of it containing toxic material, decays.
Even in areas remote from human populations, surface water contains suspended silt, organic material, decaying vegetation, and microbes from animal wastes.
As explained earlier, radiometric dating methods are based on the general principle that a particular radioactive isotope (radioactive parent or source material) incorporated in geologic material decays at a uniform rate, producing a decay product, or daughter isotope.
